LINAC2022 - List of Keywords (cavity)

Paper	Title	Other Keywords	Page
MO2AA04	Electron Ion Collider Strong Hadron Cooling Injector and ERL	electron, linac, emittance, hadron	7
	E. Wang, W.F. Bergan, F.J. Willeke BNL, Upton, New York, USA S.V. Benson, K.E. Deitrick JLab, Newport News, Virginia, USA D. Douglas Douglas Consulting, York, Virginia, USA C.M. Gulliford Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA C.E. Mayes, N.W. Taylor Xelera Research LLC, Ithaca, New York, USA J. Qiang LBNL, Berkeley, California, USA
	Funding: The work is supported by Brookhaven Science Associates, LLC under Contract No. DESC0012704 with the U.S. Department of Energy. Intra-beam Scattering (IBS) and other diffusion mechanisms in the EIC Hadron Storage Ring (HSR) degrade the beam emittances during a store, with growth times of about 2 hours at the nominal proton energies of 275GeV, 100 GeV, and 41 GeV. Strong Hadron Cooling (SHC) can maintain good hadron beam quality and high luminosity during long collision stores. A novel cooling method ’ Coherent electron Cooling (CeC) ’ is chosen as the baseline SHC method, due to its high cooling rates. An Energy Recovery Linac (ERL) is used to deliver an intense high-quality electron beam for cooling. In this paper, we discuss the beam requirements for SHC-CeC and describe the current status of the injector and ERL designs. Two designs of injector and ERL will be presented: one for dedicated SHC and another one for SHC with precooler.

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	Slides MO2AA04 [4.436 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MO2AA04
About •	Received ※ 23 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 27 August 2022 — Issue date ※ 31 August 2022
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MO1PA01	Beam Commissioning and Integrated Test of the PIP-II Injector Test Facility	MMI, cryomodule, operation, MEBT	13
	E. Pozdeyev, R. Andrews, C.M. Baffes, M. Ball, C. Boffo, R. Campos, J.-P. Carneiro, B.E. Chase, A.Z. Chen, D.J. Crawford, J. Czajkowski, N. Eddy, M. El Baz, M.G. Geelhoed, V.M. Grzelak, P.M. Hanlet, B.M. Hanna, B.J. Hansen, E.R. Harms, B.F. Harrison, M.A. Ibrahim, K.R. Kendziora, M.J. Kucera, D.D. Lambert, J.R. Leibfritz, P. Lyalyutskyy, J.N. Makara, H. Maniar, L. Merminga, R. Neswold, D.J. Nicklaus, J.P. Ozelis, D. Passarelli, N. Patel, D.W. Peterson, L.R. Prost, G.W. Saewert, A. Saini, V.E. Scarpine, A.V. Shemyakin, J. Steimel, A.I. Sukhanov, P. Varghese, R. Wang, A. Warner, G. Wu, R.M. Zifko Fermilab, Batavia, Illinois, USA V.K. Mishra, M.M. Pande, K. Singh, Vikas. Teotia BARC, Mumbai, India
	The PIP-II Injector Test (PIP2IT) facility is a near-complete low energy portion of the Superconducting PIP-II linac driver. PIP2IT comprises the warm front end and the first two PIP-II superconducting cryomodules. PIP2IT is designed to accelerate a 2 mA H⁻ beam to an energy of 20 MeV. The facility serves as a testbed for a number of advanced technologies required to operate PIP-II and provides an opportunity to gain experience with commissioning of the superconducting linac, significantly reducing project technical risks. Some PIP2IT components are contributions from international partners, who also lend their expertise to the accelerator project. The project has been successfully commissioned with the beam in 2021, demonstrating the performance required for the LBNF/DUNE. In this paper, we describe the facility and its critical systems. We discuss our experience with the integrated testing and beam commissioning of PIP2IT, and present commissioning results. This important milestone ushers in a new era at Fermilab of proton beam delivery using superconducting radio-frequency accelerators.

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	Slides MO1PA01 [2.714 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MO1PA01
About •	Received ※ 16 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 13 October 2022
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MOPOJO03	HELEN: A Linear Collider Based on Advanced SRF Technology	collider, SRF, linear-collider, linac	31
	S.A. Belomestnykh, P.C. Bhat, M. Checchin, A. Grassellino, M. Martinello, S. Nagaitsev, S. Posen, A.S. Romanenko, V.D. Shiltsev, A. Valishev, V.P. Yakovlev Fermilab, Batavia, Illinois, USA S.A. Belomestnykh Stony Brook University, Stony Brook, USA H. Padamsee Cornell University, Ithaca, New York, USA
	Funding: Work supported by the Fermi National Accelerator Laboratory, managed and operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy. This paper discusses recently proposed Higgs-Energy LEptoN (HELEN) e+e’ linear collider based on advances superconducting radio frequency technology. The collider offers cost and AC power savings, smaller footprint (relative to the ILC), and could be built at Fermilab with an Interaction Region within the site boundaries. After the initial physics run at 250 GeV, the collider could be upgraded either to higher luminosity or to higher (up to 500 GeV) energies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO03
About •	Received ※ 24 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 04 September 2022 — Issue date ※ 15 September 2022
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MOPOJO08	RF Design, Optimization and Multiphysics Study of a β = 1, 1.3 GHz Single Cell Accelerating Cavity for High-Intensity Compact Superconducting Electron Accelerator (HICSEA)	multipactoring, electron, HOM, accelerating-gradient	41
	M. Meena, A. Pathak, R. Varma IIT Mumbai, Mumbai, India
	High-energy electron accelerators have been used in water purification for several years. They are very effective for the removal of complex impurities. This study aims to design a superconducting electron beam accelerator with an output energy of 1 MeV and beam power of 40 kW for wastewater treatment. A 1.3 GHz single cell elliptic cavity with β = 1 was designed and optimized for TM010 mode and an accelerating gradient of 15 MV/m. For the optimized cavity, the RF parameters, namely, R/Q, transit time factor and geometry factor (G) were found to be 174.93 ohm, 0.67 and 276 ohm, respectively. Multiphysics studies showed that the value of R/Q for fundamental accelerating mode was 174.93 ohm. It was much higher than that of other modes, thus, HOM coupler is not required for the system. The Lorentz force detuning coefficient after stiffening the cavity iris, and the temperature rise due to the RF surface losses were found to be 0.20 Hz/(MV/m)2 and 0.085 K, respectively. It is also observed that there is no occurrence of multipacting for the designed accelerating gradient.
	Poster MOPOJO08 [1.584 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO08
About •	Received ※ 24 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 05 September 2022
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MOPOJO09	A Compact Inverse Compton Scattering Source Based on X-Band Technology and Cavity-Enhanced High Average Power Ultrafast Lasers	photon, electron, laser, linac	44
	A. Latina, R. Corsini, L.A. Dyks, E. Granados, A. Grudiev, V. Musat, S. Stapnes, W. Wuensch CERN, Meyrin, Switzerland E. Cormier CELIA, Talence, France L.A. Dyks Oxford University, Physics Department, Oxford, Oxon, United Kingdom G. Santarelli ILE, Palaiseau Cedex, France
	A high-pulse-current injector followed by a short high-gradient X-band linac is considered as a driver for a compact Inverse Compton Scattering source. We show that using a high-power ultrashort pulse laser operating in burst mode and a Fabry-Pérot enhancement cavity, X-rays with flux values over 10¹³ ph/s and photon energies up to MeV are achievable. The resulting high-intensity and high-energy X-rays allow for various applications, including cancer therapy, tomography, and nuclear waste management. A preliminary conceptual design of such a compact ICS source is presented, together with simulations of the expected performance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO09
About •	Received ※ 19 August 2022 — Revised ※ 30 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 06 September 2022
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MOPOJO11	Challenges for High-Energy X-Ray Security Screening Linacs	linac, electron, detector, photon	50
	M. Jenkins, J. Ollier, M.G. Procter Rapiscan Systems Ltd, Stoke-on-Trent, United Kingdom
	X-ray based Cargo and Vehicle Inspection (CVI) systems are used for security and customs inspections at a variety of locations. To provide the maximum flexibility many users require mobile CVI systems to allow vehicles to be screened efficiently for threats and contraband. The need for mobile systems means that the linear accelerator, and ancillary systems, used to generate the x-rays must be compact, rugged, and reliable. These systems must meet image performance tests specified by American National Standards Institute (ANSI) and the International Electrotechnical Commission (IEC). The IEC also defines a standard for material discrimination. The requirements of these standards mean that the x-ray output produced by the linac needs to be consistent during and between scans, with the stability and repeatability of the output being critical. The tolerances on the linac output to meet the performance standards combined with the need for a compact system gives an unusual challenge for the linac design. A review of how different stability measures impact the performance tests is presented. This is compared to current technologies and possible future linacs used for mobile CVI systems.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO11
About •	Received ※ 24 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022
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MOPOJO12	Design of a Compact Linac for High Average Power Radiotherapy	linac, coupling, GUI, gun	53
	C.D. Nantista, G.B. Bowden, Z. Li, M. Shumail, S.G. Tantawi SLAC, Menlo Park, California, USA B.W. Loo Stanford University, Stanford, California, USA
	We present the design of a compact, 10 MeV, 300 mA pulsed X-band linac developed for medical application. The layout, <1 m including gun, buncher, capture section and current monitor, is of a recent configuration in which the 36 main linac cavities are individually fed in parallel through side waveguide manifolds, allowing for split fabrication. Initially destined for experimental study of FLASH irradiation of mouse tumors, the design was developed as a prototype for realization of a PHASER cancer treatment machine, in which multiple linacs, powered sequentially from a common RF source, are to provide rapid treatment to patients from multiple directions without mechanical movement, delivering dosage on a time scale that essentially freezes the patient. In this paper, we focus on the RF design, beam capture optimization, mechanical design and fabrication of the linac itself, deferring discussion of other important aspects such as window and target design, experimental specification setting, radiation shielding and operations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO12
About •	Received ※ 22 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 06 September 2022
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MOPOJO16	Cryogenic Accelerator Design for Compact Very High Energy Electron Therapy	linac, coupling, distributed, electron	62
	E.J.C. Snively, V. Borzenets, G.B. Bowden, A.K. Krasnykh, Z. Li, C.D. Nantista, M. Oriunno, M. Shumail, S.G. Tantawi SLAC, Menlo Park, California, USA B.W. Loo Stanford University, Stanford, California, USA
	Funding: This research has been supported by the U.S. Department of Energy (DOE) under Contract No. DE-C02-76SF00515. We report on the development of a cryogenic X-band (11.424 GHz) accelerator to provide electron beams for Very High Energy Electron therapy. The distributed coupling linac is designed with a 135° phase advance, capable of producing a 100 MeV/m accelerating gradient in a one-meter structure using only 19 MW when operating at 77 K. This peak power will be achieved through pulse compression of a 5-8 MW few-µs pulse, ensuring compatibility with a commercial power source. We present designs of the cryogenic linac and power distribution system, as well as a room temperature pulse compressor using the HE11 mode in a corrugated cavity. We discuss scaling this compact and economical design into a 16 linac array that can achieve FLASH dose rates (> 40 Gy/s) while eliminating the downtime associated with gantry motion.
	Slides MOPOJO16 [1.320 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO16
About •	Received ※ 14 August 2022 — Revised ※ 18 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 26 September 2022
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MOPOJO17	Design and Optimization of a 100 kV DC Thermionic Electron Gun and Transport Channel for a 1.3 GHz High Intensity Compact Superconducting Electron Accelerator (HICSEA)	electron, solenoid, gun, cathode	65
	P. Nama, A. Pathak, R. Varma IIT Mumbai, Mumbai, India
	Here we present, the design and optimization of a 100 kV DC thermionic electron gun, and a transport channel that provides transverse focusing through a normal conducting solenoid and longitudinal bunching with the help of a single gap buncher for a 1.3 GHz, 40 kW, 1 MeV superconducting electron accelerator. The accelerator is proposed to treat various contaminants present in potable water resources. A 100 kV thermionic electron gun with LaB6 as its cathode material was intended to extract a maximum beam current of 500 mA. To minimize beam emittance, gun geometry i.e. cathode radius, and height and radius of the focusing electrode are optimized. The minimal obtained emittance at the gun exit is 0.3 mm.mrad. A normal conducting focusing solenoid with an iron encasing is designed and optimized to match and transport the beam from gun exit to the superconducting cavity. Finally, a 1.3 GHz ELBE type buncher is designed and optimized to bunch the electron beam for further acceleration.
	Slides MOPOJO17 [1.268 MB]
	Poster MOPOJO17 [0.813 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO17
About •	Received ※ 23 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 27 August 2022 — Issue date ※ 31 August 2022
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MOPOJO19	Programmable SLED System for Single Bunch and Multibunch Linac Operation	klystron, linac, operation, LLRF	73
	C. Christou, P. Gu, A. Tropp DLS, Oxfordshire, United Kingdom
	The Diamond Light Source pre-injector linac generates single bunch and multibunch 100 MeV electron beams for top-up and fill of the storage ring. The linac is powered by two high-power 3 GHz klystrons, and both klystrons are required for reliable injection into the booster and storage ring. In order to introduce redundancy, a SLED pulse compression cavity has been installed so that the linac can operate from just one klystron, with the second klystron held as a standby. A simple phase flip can be used to generate a high-power transient RF spike, suitable for single bunch linac operation, and a programmable amplitude and phase drive profile can be specified to generate a constant-power klystron output suitable for multibunch operation. Details are presented of design, installation and high-power operation of the SLED system, and the ability to generate a long pulse, including corrections for klystron nonlinearity and deviations from modulator flat-top, is demonstrated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO19
About •	Received ※ 09 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 08 September 2022
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MOPOPA02	Identification of the Mechanical Dynamics of the Superconducting Radio-Frequency Cavities for the European XFEL CW Upgrade	controls, FEL, SRF, experiment	76
	W.H. Syed, A. Bellandi, J. Branlard, A. Eichler DESY, Hamburg, Germany
	The European X-Ray Free-Electron Laser (EuXFEL) is to-date the largest X-ray research facility around the world which spans over 3.4 km. EuXFEL is currently being operated in a pulsed mode with a repetition rate of 10Hz. One upgrade scenario consists of operating the EuXFEL also in a Continuous-Wave (CW) mode of operation to improve the quality of experiments. This upgrade brings new challenges and requires new algorithms to deal with controlling a stable accelerating field inside the Superconducting Radiofrequency (SRF) accelerating cavities and keeping them on resonance in this new mode of operation. The purpose of this research work is to identify the mechanical dynamics of the cavities which will facilitate the development of the resonance controller for the CW upgrade. To this extent, experiments were conducted at a test bench. For the first time, in this work, two different types of spectrally rich excitation signals: multi-sine and stepped-sine are used to excite the mechanical dynamics of the cavities using the piezo actuator. After the analysis of experimental data, mechanical modes are successfully identified and will be used to design the controller.
	Poster MOPOPA02 [0.687 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA02
About •	Received ※ 23 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 26 August 2022 — Issue date ※ 01 September 2022
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MOPOPA03	Beam-Transient-Based LLRF Voltage Signal Calibration for the European XFEL	FEL, LLRF, linac, operation	80
	N. Walker, V. Ayvazyan, J. Branlard, S. Pfeiffer, Ch. Schmidt DESY, Hamburg, Germany
	The European XFEL linac consists of 25 superconducting RF (SRF) stations. With the exception of the first station which is part of the injector, each station comprises 32 1.3-GHz SRF TESLA cavities, driven by a single 10-MW klystron. A sophisticated state-of-the-art low-level RF (LLRF) system maintains the complex vector sum of each RF station. Monitoring and maintaining the calibration of the cavity electric field (gradient) probe signals has proven critical in achieving the maximum energy performance and availability of the SRF linac. Since there are no dedicated diagnostics for cross-checking calibration of the LLRF system, a procedure has been implemented based on simultaneously measuring the beam transient in open-loop operation of all cavities. Based on methods originally developed at FLASH, the European XFEL procedure makes use of automation and the XFEL LLRF DAQ system to provide a robust and relatively fast (minutes) way of extracting the transient data, and is now routinely scheduled once per week. In this paper, we will report on the background, implementation, analysis methods, typical results, and their subsequent application for machine operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA03
About •	Received ※ 13 August 2022 — Revised ※ 23 August 2022 — Accepted ※ 14 September 2022 — Issue date ※ 27 September 2022
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MOPOPA13	200 MV Record Voltage of vCM and LCLS-II-HE Cryomodules Production Start Fermilab	cryomodule, SRF, vacuum, plasma	95
	T.T. Arkan, D. Bafia, D.J. Bice, J.N. Blowers, A.T. Cravatta, B. Giaccone, C.J. Grimm, B.D. Hartsell, J.A. Kaluzny, M. Martinello, T.H. Nicol, Y.M. Orlov, S. Posen Fermilab, Batavia, Illinois, USA M. Checchin SLAC, Menlo Park, California, USA
	Funding: Department of Energy The Linac Coherent Light Source (LCLS) is an X-ray science facility at SLAC National Accelerator Laboratory. The LCLS-II project (an upgrade to LCLS) is in the commissioning phase; the LCLS-II-HE (High Energy) project is another upgrade to the facility, enabling higher energy operation. An electron beam is accelerated using superconducting radio frequency (SRF) cavities built into cryomodules. It is planned to build 24 1.3 GHz standard cryomodules and 1 1.3 GHz single-cavity Buncher Capture Cavity (BCC) cryomodule for the LCLS-II-HE project. Fourteen of these standard cryomodules and one BCC are planned to be assembled and tested at Fermilab. Procurements for standard cryomodule components are nearing completion. The first LCLS-II-HE cryomodule, referred to as the verification cryomodule (vCM) was assembled and tested at Fermilab. Fermilab has completed the assembly of the second cryomodule. This paper presents LCLS-II-HE cryomodule production status at Fermilab, emphasizing the changes done based on the successes, challenges, mitigations, and lessons learned from LCLS-II; validation of the changes with the excellent vCM results.
	Poster MOPOPA13 [1.975 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA13
About •	Received ※ 10 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 09 September 2022
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MOPOPA15	Three Years of Operation of the SPIRAL2 SC LINAC- RF Feedback	linac, LLRF, controls, operation	98
	M. Di Giacomo, M. Aburas, P.-E. Bernaudin, O. Delahaye, A. Dubosq, A. Ghribi, J.-M. Lagniel, J.F. Leyge, G. Normand, A.K. Orduz, F. Pillon, L. Valentin GANIL, Caen, France F. Bouly LPSC, Grenoble Cedex, France S. Sube CEA-DRF-IRFU, France
	The superconducting LINAC of SPIRAL2 at the GANIL facility has been in operation since October 2019. The accelerator uses 12 low beta and 14 high beta supercon-ducting quarter wave cavities, cooled at 4°K, working at 88 MHz. The cavities are operated at a nominal gradient of 6.5 MV/m and are independently powered by a LLRF and a solid-state amplifier, protected by a circulator. Pro-ton and deuteron beam currents can reach 5 mA and beam loading perturbation is particularly strong on the first cavities, as they are operated at field levels much lower than the nominal one. This paper presents a feedback after three years of oper-ation, focuses on the RF issues, describing problems and required improvement on the low level, control and pow-er systems
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA15
About •	Received ※ 14 August 2022 — Revised ※ 17 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 02 September 2022
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MOPOPA17	RF Commissioning of the First-of-Series Cavity Section of the Alvarez 2.0 at GSI	DTL, operation, vacuum, coupling	106
	M. Heilmann, L. Groening, C. Herr, M. Hoerr, S. Mickat, B. Schlitt, G. Schreiber GSI, Darmstadt, Germany
	The existing post-stripper DTL of the GSI UNILAC will be replaced with the new Alvarez 2.0 DTL to serve as the injector chain for the Facility of Antiproton and Ion Research (FAIR). The 10⁸.4 MHz Alvarez 2.0 DTL with a total length of 55 meters has an input energy of 1.36 MeV/u and the output energy is 11.32 MeV/u. The presented First-of-Series (FoS) cavity section with 11 drift tubes and a total length of 1.9 m is the first part of the first cavity of the Alvarez 2.0 DTL. After copper plating and assembly of the cavity the RF-conditioning started in July 2021. These proceeding gives an overview on the results of the successfully RF-conditioning to reach the necessary gap voltage for uranium operation including a comfortable safety margin.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA17
About •	Received ※ 24 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022
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MOPOPA19	Preparation for Commissioning with Beam of "Advanced Demonstrator" Module with Heavy Ion Beam	linac, heavy-ion, MMI, solenoid	114
	M. Miski-Oglu, W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, T. Kürzeder, S. Lauber, J. List, S. Yaramyshev HIM, Mainz, Germany W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, S. Yaramyshev GSI, Darmstadt, Germany W.A. Barth, F.D. Dziuba, S. Lauber, J. List KPH, Mainz, Germany H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany
	The integration of the accelerator components in to the cryogenic module prototype (Advanced Demonstrator) is a major milestone of the R&D for the superconducting heavy ion continuous wave linear accelerator HELIAC at GSI. The HELIAC is joint project of Helmholtz Institute Mainz (HIM) and GSI developed in collaboration with IAP Goethe University Frankfurt. This module is equipped with three superconducting (sc) Cross bar H-mode (CH) acceleration cavities CH0-CH2 and a sc rebuncher cavity, as well as two sc solenoids. The commissioning of the cryogenic module with Argon beam at GSI is scheduled for August 2023. In preparation for the beam test activities, the beamline, which connects the High Charge State Injector (HLI) with the testing area, has been installed. The beamline comprises a pair of phase probes for Time Of Flight (TOF) measurement of the incoming beam energy, quadrupole lenses and a 4-gap RF-buncher cavity. The beam diagnostics bench behind the cryo module is equipped with phase probe pairs, a slit-grid device, a bunch shape monitor (Feshenko monitor) for measurements of the longitudinal beam profile. The bench allows complete 6d characterization of the ion beam.
	Poster MOPOPA19 [3.074 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA19
About •	Received ※ 24 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 04 September 2022
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MOPOPA20	Q Drop Tendency of Half-Wave Resonator Cavity	radiation, ECR, vacuum, superconducting-cavity	118
	Y. Jung, H. Jang, H. Kim, H. Kim, J.W. Kim IBS, Daejeon, Republic of Korea S. Jeon Kyungpook National University, Daegu, Republic of Korea
	All HWRs (half-wave resonator superconducting cavities) have been fabricated and installed in the low energy section of the LINAC in IBS. All HWR cavities have been tested (vertical tests, VT) both at 4.2 K and 2.1 K cryogenic surroundings although operating temperature of HWRs is 2.1 K. Good cavities of high quality factors showed the Q drop tendency of 2.1 k were very similar to that of 4.2 K. However, in many cases, Q drop tendency of 2.1 K were not similar with 4.2 K, rather Q decreased more rapidly than 4.2 K which means the surface resistance of the cavity rapidly increased at 2 K surrounding. In this study, we will report that various Q results of HWRs and compare their Q drop tendency as a function of temperature, 2.1 K and 4.2 K.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA20
About •	Received ※ 23 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022
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MOPOGE01	Linac Design within HITRIplus for Particle Therapy	linac, synchrotron, rfq, operation	134
	U. Ratzinger, H. Höltermann, B. Koubek, H. Podlech BEVATECH, Frankfurt, Germany M. Vretenar CERN, Meyrin, Switzerland
	Funding: EU Horizon 2020 Grant agreement No 101008548 Within the EU H2020 project HITRIplus for the development of cancer therapy with heavy ions a linac was designed. It is evolving from the concept of the 4 European cancer therapy centers applying light ions up to carbon. The new linac will in its simpliest version allow C⁴⁺ - beam injection into synchrotrons at 5 A MeV, with high beam transmission and allowing currents up to 5 mA alpha - particles. An advanced ECR - ion source will inject into an RFQ - IH-DTL combination. The DTL concept allows upgraded versions for A/q - values up to two and with beam energies of 7.1 A MeV from IH - tank2 and 10 A MeV from IH-tank3. The higher beam injection energies for light ions allow a relaxed synchrotron operation at lowest magnetic field levels. A main argument for the DTL extensions however is an additional linac function as radioisotope facility driver. The 7.1 A MeV are especially defined for the clean production of 211At, which may play a future role in cancer therapy. The linac will allow for high duty factors - up to 10%, to fulfil the needs for efficient radioisotope production. Solid state amplifiers with matched design RF power levels (up to 600 kW for IH3) will be used.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE01
About •	Received ※ 24 August 2022 — Revised ※ 27 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 07 September 2022
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MOPOGE04	Cell Geometry Optimization for Dipole Kick Correction in a High-Frequency IH Structure	dipole, linac, DTL, impedance	146
	R. López López, P. Calvo, D. Gavela, J. Giner Navarro, G. Moreno, C. Oliver, J.M. Pérez Morales CIEMAT, Madrid, Spain M.C. Battaglia, J.M. Carmona AVS, Elgoibar, Spain A.M. Lombardi CERN, Meyrin, Switzerland
	Funding: CIEMAT Given the asymmetry in the stem configuration of an IH-DTL structure, an electric dipole component is always present between drift tubes, and it is especially significant for reduced dimensions in high-frequency regimes. Here we study the effect of different modifications of the drift tubes geometry of a 750 MHz IH-DTL to eliminate the impact of the dipole component in the transverse beam dynamics. Tracking simulations through a single cell are also performed to assess the outcomes in particle’s trajectory offset and angle.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE04
About •	Received ※ 24 August 2022 — Revised ※ 27 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 04 September 2022
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MOPOGE05	Effect of High-Magnetic Field Region Geometry on the Efficiency of a 750 MHz IH Structure	linac, simulation, impedance, software	150
	G. Moreno, P. Calvo, D. Gavela, J. Giner Navarro, R. López López, C. Oliver, J.M. Pérez Morales CIEMAT, Madrid, Spain M.C. Battaglia, J.M. Carmona AVS, Elgoibar, Spain A.M. Lombardi CERN, Meyrin, Switzerland
	Funding: CIEMAT High frequency structures generally translate to high efficiency performances thanks to reduced surfaces of the inner cavity. Two round-profiles geometry and some variations of two important parameters of a 750 MHz IH-DTL are proposed in this paper in order to improve shunt impedance performance regarding an existing solution with flat-walled cavity developed by CERN. The proposed designs are shaped such that they guarantee an easy connection of RF and vacuum auxiliaries. Electromagnetic simulations are checked with CST Microwave Studio.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE05
About •	Received ※ 20 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 27 August 2022 — Issue date ※ 13 October 2022
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MOPOGE06	Automatic RF Conditioning of S-Band Cavities for Commercial Proton Therapy Linacs	vacuum, controls, linac, GUI	154
	S. Benedetti, M. Cerv, S. Magnoni, J.L. Navarro Quirante, S.G. Soriano AVO-ADAM, Meyrin, Switzerland
	The CERN spinoff company ADAM owned by Advanced Oncotherapy plc (AVO-ADAM) is completing the construction and testing of its first LIGHT (Linac for Image-Guided Hadron Therapy) system. Each LIGHT machine is composed by 20 accelerating modules: one 750 MHz RFQ, four 3 GHz Side-Coupled Drift Tube Linac (SCDTL) and 15 3 GHz Coupled-Cavity Linac (CCL). The company aims at delivering several similar LIGHT machines in the next years. A prerequisite to achieve such goal is the capability to complete the RF conditioning of the accelerating modules in a systematic and automatic way, with minimal inputs from RF engineers. In the past years ADAM developed an automatic conditioning system capable of increasing the main conditioning parameters ’ RF power, pulse width, repetition rate ’ while controlling the cavity breakdown rate and vacuum level. The system has been so far tested on about twenty accelerating structures with different brazing methodologies and RF accelerating voltages, proving its robustness. This paper discusses the ADAM automatic conditioning system design and its implementation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE06
About •	Received ※ 13 August 2022 — Revised ※ 17 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 31 August 2022
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MOPOGE07	High Power RF Transmission Lines of the Light Proton Therapy Linac	network, linac, proton, controls	158
	J.L. Navarro Quirante, D. Aguilera Murciano, S. Benedetti, G. Castorina, C. Cochrane, G. De Michele, J. Douthwaite, A. Eager, S. Fanella, M. Giles, D. Kaye, V.F. Khan, J. Mannion, J. Morris, J.F. Orrett, N. Pattalwar, E. Rose, D. Soriano Guillén AVO-ADAM, Meyrin, Switzerland
	The LIGHT (Linac for Image-Guided Hadron Therapy) machine is designed to accelerate a proton beam up to 230 MeV to treat deep seated tumours. The machine consists of three different kinds of accelerators: RFQ (Radio-Frequency Quadrupole), SCDTL (Side Coupled Drift Tube Linac) and CCL (Coupled Cavity Linac). These accelerating structures are fed with RF power at 750 MHz (RFQ) and 3 GHz (SCDTLs and CCLs). This power is delivered to the accelerating structure via the high power RF transmission network (RF network). In addition, the RF network needs to offer other functionalities, like protection of the high RF power feeding stations, power splitting, phase and amplitude control and monitoring. The maximum power handling of the RF network corresponds to a peak RF power of 8 MW and an average RF power of 9 kW. It functions either in Ultra-High Vacuum (UHV) conditions at an ultimate operating pressure of 10^-7 mbar, or under pressurized gas. The above listed requirements involve different challenges. In this contribution we exhibit the main aspects to be considered based on AVO experience during the commissioning of the RF network units.
	Poster MOPOGE07 [1.075 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE07
About •	Received ※ 22 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 02 September 2022
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MOPOGE08	Low Level RF System of the Light Proton Therapy Linac	LLRF, linac, controls, rfq	161
	D. Soriano Guillén, S. Benedetti, M. Cerv, G. De Michele, Ye. Ivanisenko AVO-ADAM, Meyrin, Switzerland
	The LIGHT (Linac for Image-Guided Hadron Therapy) project was initiated to develop a modular proton accelerator delivering beam with energies up to 230 MeV for cancer therapy. The machine consists of three different kinds of accelerating structures: RFQ (Radio-Frequency Quadrupole), SCDTL (Side Coupled Drift Tube Linac) and CCL (Coupled Cavity Linac). These accelerating structures operate at 750 MHz (RFQ) and 3 GHz (SCDTL, CCL). The accelerator RF signals are generated, distributed, and controlled by a Low-Level RF (LLRF) system. The LIGHT LLRF system is based on a commercially available solution from Instrumentation Technologies with project specific customization. This LLRF system features high amplitude and phase stability, monitoring of the RF signals from the RF network and the accelerating structures at 200 Hz, RF pulse shaping over real-time interface integrated, RF breakdown detection, and thermal resonance frequency correction feedback. The LLRF system control is integrated in a Front-End Controller (FEC) which connects it to the LIGHT control system. In this contribution we present the main features of the AVO LLRF system, its operation and performance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE08
About •	Received ※ 16 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 05 September 2022
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MOPOGE10	A Medical Linac for Affordable Proton Therapy	proton, linac, cyclotron, radiation	167
	S. Hunt, J. Adélise, W.D. Klotz, R. Seviour, E.D. van Garderen Alceli Limited, Aberdeen, United Kingdom D. Correia PSI, Villigen PSI, Switzerland
	Proton Therapy (PT) was first proposed in the 1940s. Application of this knowledge was largely led over the next fifty years by accelerator laboratories, but now also by commercial companies. Availability of PT is increasing but is limited by three factors: facility size, prompt/induced radiation, and treatment cost. Compact cyclotrons/synchro cyclotrons for single-room facilities have reduced space requirements. linacs can avoid high radiation levels. Yet treatment costs have remained stubbornly high, driven largely by maintenance and staffing costs over the typical 20-30 year facility lifetime. Current technology cannot simultaneously reduce these three factors. By using a long linac, the Alceli approach sacrifices size limitations, to gain massive improvements in treatment cost and radiation levels. Quadrupling the length of a linac results in a sixteen-fold reduction in RF power per cavity. Along with other innovations in our design, this leads to a modular warm linac with distributed solid-state RF amplification, easy and cheap to manufacture and maintain, requiring no water cooling, and a treatment cost of 1/10th of current facilities, making PT much more affordable.
	Slides MOPOGE10 [1.934 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE10
About •	Received ※ 15 August 2022 — Revised ※ 23 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022
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MOPOGE11	Update on the First 3D Printed IH-Type Linac Structure - Proof-of-Concept for Additive Manufacturing of Linac RF Cavities	vacuum, linac, simulation, experiment	170
	H. Hähnel, A. Ateş, U. Ratzinger IAP, Frankfurt am Main, Germany
	Funding: This research was funded by BBMBF grant number 05P21RFRB2. Additive manufacturing ("AM" or "3D printing") has become a powerful tool for rapid prototyping and manufacturing of complex geometries. A 433 MHz IH-DTL cavity has been constructed to act as a proof of concept for additive manufacturing of linac components. In this case, the internal drift tube structure has been produced from 1.4404 stainless steel using AM. We present the concept of the cavity as well as first results of vacuum testing, materials testing and low level rf measurements. Vacuum levels sufficient for linac operation have been reached with the AM linac structure.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE11
About •	Received ※ 22 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 02 September 2022
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MOPOGE12	Cavity R&D for HBS Accelerator	simulation, neutron, brilliance, proton	174
	N.F. Petry, K. Kümpel, S. Lamprecht, O. Meusel, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany
	The demand for neutrons of various types for research is growing day by day worldwide. To meet the growing demand the Jülich High Brilliance Neutron Source (HBS) is in development. It is based on a high power linear proton accelerator with an end energy of 70 MeV and a proton beam current of 100 mA. The main part of the accelerator consists of about 45 CH-type cavities. As the current beam dynamic layout is still work in progress the number of cavities can change for the final design. For this beam dynamic layout the design of the CH-type cavities was optimized to handle the high accelerating gradient. The results of the performance of the CH-type cavities will be presented in this paper.
	Poster MOPOGE12 [1.286 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE12
About •	Received ※ 17 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 15 September 2022
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MOPOGE13	Acceleration Efficiency of TE-Mode Structures for Proton Linacs	DTL, proton, simulation, impedance	177
	J. Tamura, Y. Kondo, T. Morishita JAEA/J-PARC, Tokai-mura, Japan F. Naito, M. Otani KEK, Tokai, Ibaraki, Japan
	Various types of cavity structures are typically used in hadron linacs, depending on the energy range of the beam particle. This is especially the case in a normal-conducting linac, because the cavity’s acceleration efficiency varies with the velocity of the synchronous particle. For low-energy proton acceleration, while Alvarez drift-tube linacs (DTLs) are the most prevalent, TE-mode accelerating structures, which could also be called H-mode structures, are also widely used immediately after an initial radiofrequency quadrupole linac (RFQ). At present, the representative structures of TE modes are interdigital H-mode (IH) DTL and crossbar H-mode (CH) DTL, which are based on the TE11-mode pillbox cavity and TE21-mode pillbox cavity, respectively. In this presentation, acceleration efficiency of TE-mode structures including higher-order TE-modes such as TE31 and TE41 was comparatively reviewed with Alvarez DTL. This study shows that IH-DTL and CH-DTL have a larger shunt impedance than Alvarez DTL for proton acceleration below 10 MeV, and furthermore for the TEm1-mode structures, the rotational symmetry of the electric field improves with increasing angular index m.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE13
About •	Received ※ 30 August 2022 — Revised ※ 06 September 2022 — Accepted ※ 14 September 2022 — Issue date ※ 26 September 2022
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MOPOGE14	Current Status of the Spoke Cavity Prototyping for the JAEA-ADS Linac	linac, simulation, status, SRF	180
	J. Tamura, Y. Kondo, F. Maekawa, S.I. Meigo, B. Yee-Rendón JAEA/J-PARC, Tokai-mura, Japan T. Dohmae, E. Kako, H. Sakai, K. Umemori KEK, Ibaraki, Japan
	The Japan Atomic Energy Agency (JAEA) has proposed an accelerator-driven subcritical system (ADS) to efficiently reduce high-level radioactive waste generated at nuclear power plants. One of the challenging R&D aspects of ADS is the reliability of the accelerator. In preparation for the full-scale design of the CW proton linac for the JAEA-ADS, we are now prototyping a low-beta (around 0.2) single spoke cavity. Since there is no experience in Japan in manufacturing a superconducting spoke cavity, prototyping and performance testing of the cavity is essential to ensure the feasibility of the JAEA-ADS linac. In the Japanese fiscal year 2021, we have started welding cavity parts together. By preliminarily examining the electron beam welding conditions, each press-formed niobium part was joined with a smooth welding bead. The current status of the spoke cavity prototyping for the JAEA-ADS linac is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE14
About •	Received ※ 01 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 14 September 2022 — Issue date ※ 26 September 2022
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MOPOGE16	Development of High-Gradient Accelerating Structures for Proton Radiography Booster at LANSCE	booster, linac, proton, coupling	188
	S.S. Kurennoy, Y.K. Batygin, E.R. Olivas LANL, Los Alamos, New Mexico, USA
	Increasing energy of proton beam at LANSCE from 800 MeV to 3 GeV improves radiography resolution ~10 times. We propose accomplishing this energy boost with a compact cost-effective linac based on normal conducting high-gradient (HG) RF accelerating structures. Such an unusual proton linac is feasible for proton radiography (pRad), which operates with very short beam (and RF) pulses. For a compact pRad booster at LANSCE, we have developed a multi-stage design: a short L-band section to capture and compress the 800-MeV proton beam from the existing linac followed by the main HG linac based on S- and C-band cavities, and finally, by an L-band de-buncher. Here we present details of development, including EM and thermal-stress analysis, of proton HG structures with distributed RF coupling for the pRad booster. A short test structure is designed specifically for measurements at the LANL C-band RF Test Stand. S.S. Kurennoy, Y.K. Batygin. IPAC21, MOPAB210.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE16
About •	Received ※ 23 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 03 September 2022
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MOPOGE17	CST Modeling of the LANSCE Coupled-Cavity Linac	alignment, linac, quadrupole, emittance	191
	S.S. Kurennoy, Y.K. Batygin LANL, Los Alamos, New Mexico, USA
	The 800-MeV proton linac at LANSCE consists of a drift-tube linac, which brings the beam to 100 MeV, followed by 44 modules of a coupled-cavity linac (CCL). Each CCL module contains multiple tanks, and it is fed by a single 805-MHz klystron. CCL tanks are multi-cell blocks of identical re-entrant side-coupled cavities, which are followed by drifts with magnetic quadrupole doublets. Bridge couplers - special cavities displaced from the beam axis - electromagnetically couple CCL tanks over such drifts within a module. We have developed 3D CST models of CCL tanks. The models are used to calculate electromagnetic fields in the tanks. Beam dynamics is modelled in CST for bunch trains with realistic beam distributions using the calculated RF fields and quadrupole magnetic fields. Beam dynamics results are crosschecked with other multi-particle codes and applied to evaluate effects of CCL misalignments.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE17
About •	Received ※ 22 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 02 September 2022
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MOPOGE21	A Superconducting 217 MHz Single Spoke Cavity for the Helmholtz Linear Accelerator at GSI	simulation, linac, resonance, SRF	200
	F.D. Dziuba, K. Aulenbacher, W.A. Barth, V. Gettmann, T. Kürzeder, J. List, M. Miski-Oglu HIM, Mainz, Germany K. Aulenbacher, W.A. Barth, F.D. Dziuba KPH, Mainz, Germany K. Aulenbacher, W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu, S. Yaramyshev GSI, Darmstadt, Germany T. Conrad, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany
	Funding: Work supported by GSI, HIM, BMBF Contr. No. 05P18UMRB2 A new superconducting (SC) continuous wave (CW) linac, providing high efficient heavy ion acceleration above the coulomb barrier, is going to be built at GSI to fulfill the upcoming demands in the research field of super heavy element (SHE) synthesis. The so called HELIAC (HElmholtz LInear ACcelerator) delivers ion beams in the energy range of 3.5 MeV/u and 7.3 MeV/u with a mass to charge ratio (A/z) of up to 6. Superconducting multi-gap crossbar-H-mode (CH) cavities with a resonance frequency of 217 MHz are used for beam acceleration. In addition, SC single spoke buncher cavities should ensure longitudinal beam matching to the corresponding CH sections. Therefore, the first 217 MHz single spoke cavity with beta 0.07 has been developed at HIM/GSI and built at an industrial partner. In this paper the design of the cavity and first RF measurements during manufacturing are presented.
	Poster MOPOGE21 [2.619 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE21
About •	Received ※ 18 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 27 August 2022 — Issue date ※ 31 August 2022
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MOPOGE23	Conservation of Quality Factor for Superconducting Cavity and Heartbeat under Relativistic Motion	acceleration, superconducting-cavity, resonance, ECR	204
	H. Kim IBS, Daejeon, Republic of Korea
	Funding: This research was supported by the Rare Isotope Science Project of Institute for Basic Science funded by Ministry of Science and National Research Foundation of Korea (NRF-2013M7A1A1075764). The conservation of quality factor under relativistic motion is applied to the superconducting cavity as well as the heartbeat of mammal. The quality factor of the superconducting cavity is conserved under relativistic motion. The frequency of the cavity decreases and the decay time increases as the velocity and acceleration are increased. The quality factor of the superconducting cavity is comparable with the total heartbeat of the mammal. The quality factor for the heartbeat of the mammal representing the total number of heartbeat is also conserved under relativistic motion. Therefore, the heart rate is inversely proportional to the life expectancy under relativistic motion.
	Poster MOPOGE23 [0.765 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE23
About •	Received ※ 25 July 2022 — Revised ※ 23 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 02 September 2022
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MOPOGE24	Understanding Q Slope of Superconducting Cavity with Magnetic Defect and Field Emission	superconducting-cavity, radiation, ECR, cryomodule	208
	H. Kim, Y. Jung, H. Kim, J.W. Kim IBS, Daejeon, Republic of Korea S. Jeon Kyungpook National University, Daegu, Republic of Korea
	Funding: This research was supported by the RISP of ibs funded by the Ministry of Science and the National Research Foundation (NRF) of the Republic of Korea under Contract 2013M7A1A1075764. RF test for quarter-wave resonator (QWR) and half-wave resonator (HWR) superconducting cavities is performed at low temperature. The quality factors of the superconducting cavities are measured as a function of accelerating field. The magnetic heating effect for the quarter-wave resonator (QWR) is studied. For the half-wave resonator (HWR), the Q slope degradation is investigated with x-ray radiation and field emission.
	Slides MOPOGE24 [2.506 MB]
	Poster MOPOGE24 [1.174 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE24
About •	Received ※ 25 July 2022 — Revised ※ 18 August 2022 — Accepted ※ 23 August 2022 — Issue date ※ 12 October 2022
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MOPOGE25	Rf Measurement and Characterisation of European Spallation Source Cavities at UKRI-STFC Daresbury Laboratory and DESY	radiation, detector, cryomodule, MMI	212
	P.A. Smith, A.E.T. Akintola, K.D. Dumbell, M.J. Ellis, S. Hitchen, P.C. Hornickel, C.R. Jenkins, A.J. May, P.A. McIntosh, K.J. Middleman, A.J. Moss, S.M. Pattalwar, M.D. Pendleton, J.O.W. Poynton, A.E. Wheelhouse, S. Wilde STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom G. Jones, M. Lowe, D.A. Mason, G. Miller, J. Mutch, A. Oates, J.T.G. Wilson STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom K.J. Middleman Cockcroft Institute, Warrington, Cheshire, United Kingdom D. Reschke, L. Steder, M. Wiencek DESY, Hamburg, Germany
	The Accelerator Science and Technology Centre (ASTeC) is responsible for delivering 88 High Beta (HB) cavities as part of the European Spallation Source (ESS) facility in Sweden. The bulk Niobium Superconducting Radio Frequency (SRF) cavities operate at 704 MHz. They have been fabricated in industry and are currently being tested at Daresbury Laboratory and Deutsches Elektronen-Synchrotron (DESY). They will then be delivered to Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA) Saclay, France for integration into cryomodules. To date 50 cavities have been conditioned and evaluated and 36 cavities have been delivered to CEA. This paper discusses the experiences and testing of the cavities performed to date at both sites
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE25
About •	Received ※ 24 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 04 September 2022
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MOPORI08	Beam Mapping Linearity Improvement in Multi-Dimensional Bunch Shape Monitor	electron, focusing, detector, operation	239
	S.V. Kutsaev, R.B. Agustsson, A.C. Araujo Martinez, A. Moro, A.Yu. Smirnov, K.V. Taletski RadiaBeam, Santa Monica, California, USA A.V. Aleksandrov, A.A. Menshov ORNL, Oak Ridge, Tennessee, USA
	Funding: This work was supported by the U.S. Department of Energy , Office of Basic Energy Sciences, under contract DE-SC0020590. RadiaBeam is developing a Bunch Shape Monitor (BSM) with improved performance that incorporates three major innovations. First, the collection efficiency is im-proved by adding a focusing field between the wire and the entrance slit. Second, a new design of an RF deflector improves beam linearity. Finally, the design is augmented with both a movable wire and a microwave deflecting cavity to add functionality and enable measuring the transverse profile as a wire scanner. In this paper, we pre-sent the design of the BSM and its sub-systems.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI08
About •	Received ※ 24 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 02 September 2022 — Issue date ※ 09 September 2022
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MOPORI12	Development of Commercial RFQ Toward CW Applications	rfq, MMI, operation, neutron	255
	H. Yamauchi, M. Masuoka Time Corporation, Hiroshima, Japan
	TIME Co. developed a new 4-vane RFQ structure that can be used for a very high-duty factor operation. We eliminated the tuners to flatten the field distribution. The tuners increase RF contacts which may trigger unex-pected local heat spots and subsequent discharges. In addition, we hollowed out the entire vane to achieve large cooling water channels. A high-power test showed that the commissioning was completed within one day. We could input a nominal RF power without experienc-ing almost any discharge. The applied duty factor was 5 % at the 200 MHz resonant frequency, and the meas-ured frequency shift was not detected. These activities have been carried out in collaboration with Tokyo Institute of Technology and RIKEN.
	Slides MOPORI12 [1.877 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI12
About •	Received ※ 26 August 2022 — Revised ※ 04 September 2022 — Accepted ※ 27 September 2022 — Issue date ※ 29 September 2022
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MOPORI18	Overview of STFC Daresbury Laboratory Vacuum Operations for the Testing of ESS High Beta Cavities.	vacuum, SRF, operation, detector	268
	S. Wilde, K.J. Middleman, M.D. Pendleton, J.O.W. Poynton STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom D.A. Mason, G. Miller, J. Mutch STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom K.J. Middleman Cockcroft Institute, Warrington, Cheshire, United Kingdom
	This paper describes the vacuum systems and operations that are used at the STFC Daresbury Laboratory SuRF lab during cold RF testing of ESS high beta RF accelerating cavities. Dedicated slow pump slow vent (SPSV) systems are used to perform vacuum acceptance testing of each cavity before, during and after cold RF testing. Details of the vacuum systems, support facilities, acceptance criteria and test results will be discussed in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI18
About •	Received ※ 24 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 02 September 2022 — Issue date ※ 09 September 2022
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MOPORI20	Fabrication, Field Measurement, and Testing of a Compact RF Deflecting Cavity for ELBE	pick-up, resonance, simulation, vacuum	271
	T.G. Hallilingaiah, P. Michel, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany A. Arnold, S. Köppen, P. Michel HZDR, Dresden, Germany U. van Rienen University of Rostock, Rostock, Germany
	A transverse deflecting cavity is being developed for the electron linac ELBE to separate the bunches into two or more beamlines so that multiple user experiments can be carried out simultaneously. A normal conducting double quarter-wave cavity has been designed to deliver a transverse kick of 300 kV when driven by an 800 W solid-state amplifier at 273 MHz. The main challenges in fabrication were machining the complex cavity parts with high precision, pre-tuning the cavity frequency, and the final vacuum brazing within the tolerances, which are described in this paper. The reason for a low intrinsic quality factor measured during the low power test was investigated, and suitable steps were taken to improve the quality factor. The cavity field profiles obtained from the bead-pull measurement matched the simulation results. Further, the cavity was driven up to 1 kW using a modified pick-up antenna, and eventually, vacuum conditioning of the cavity was accomplished. The cavity fulfils the design requirements and is ready for beam tests.
	Poster MOPORI20 [4.325 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI20
About •	Received ※ 14 August 2022 — Revised ※ 15 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 07 September 2022
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MOPORI22	High-Power Test of an APF IH-DTL Prototype for the Muon Linac	linac, DTL, experiment, simulation	275
	Y. Nakazawa, H. Iinuma Ibaraki University, Ibaraki, Japan E. Cicek, H. Ego, K. Futatsukawa, N. Kawamura, T. Mibe, S. Mizobata, N. Saito, M. Yoshida KEK, Ibaraki, Japan N. Hayashizaki Research Laboratory for Nuclear Research, Tokyo Institute of Technology, Tokyo, Japan Y. Iwata NIRS, Chiba-shi, Japan R. Kitamura, Y. Kondo, T. Morishita JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan M. Otani J-PARC, KEK & JAEA, Ibaraki-ken, Japan Y. Sue, K. Sumi, M. Yotsuzuka Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan Y. Takeuchi Kyushu University, Fukuoka, Japan T. Yamazaki KEK, Tokai Branch, Tokai, Naka, Ibaraki, Japan H.Y. Yasuda University of Tokyo, Tokyo, Japan
	A muon linac is under development for a new muon g-2/EDM experiment at J-PARC. The muons are cooled to about room temperature and then re-accelerated to 212 MeV by four linear accelerators to produce a low-emittance muon beam. In the low-beta section, a short-range acceleration cavity with high efficiency needs to be developed to suppress the decay of muons. We propose a 324 MHz inter-digital H-mode drift-tube linac (IH-DTL) with high acceleration efficiency. The cavity can be downsized by introducing the alternating phase focusing (APF) method that provides transverse focusing only with an E-field. We have developed a prototype cavity that accelerates muons up to 1.3 MeV to demonstrate the principle. In this paper, the result of the high power test of the APF IH-DTL prototype is reported.
	Poster MOPORI22 [10.978 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI22
About •	Received ※ 13 August 2022 — Revised ※ 16 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 01 September 2022
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MOPORI24	Monte Carlo Model of High-Voltage Conditioning and Operation	simulation, linac, HOM, vacuum	283
	W.L. Millar, W. Wuensch CERN, Meyrin, Switzerland G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
	To synthesise the experimental results and theory pertaining to high-field phenomena, a model has been developed to simulate the conditioning and operation of high-field systems. By using a mesh-based method, the high-field conditioning of any arbitrary geometry and surface electric field distribution may be simulated for both RF and DC devices. Several phenomena observed in previous high-field tests such as the probabilistic behaviour of vacuum arcs and the inhomogeneous distribution of arc locations are described by this approach.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI24
About •	Received ※ 20 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 15 September 2022
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MOPORI26	Limits on Standing Wave Cavity Performance Due to Thermal Effects	simulation, linac, proton, DTL	287
	S.J. Smith, G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
	After an RF cavity has been designed, a thermal analysis is typically performed to assess the effects of RF heating on the operating frequency and field flatness. A multi-physics approach (coupled electromagnetic, thermal, and mechanical) is normally employed, sometimes combined with computational fluid dynamics (CFD) simulations to incorporate flowing water, which is used for cooling in normal conducting structures. Performing a CFD analysis can add significant time to the design process because of the long and complex simulations and instead, approximations of the heat transfer coefficients and inlet/outlet water temperature rises are made and used directly in the multi-physics analysis. In this work, we first explore the limits of these approximations, identifying when they apply and how accurate they are. We then investigate different pipe geometries and water flow rates to find the thermal limits from RF heating on cavity performance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI26
About •	Received ※ 17 August 2022 — Revised ※ 20 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 15 September 2022
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TU1AA02	Compact, Turn-Key SRF Accelerators	cryomodule, SRF, operation, controls	290
	N.A. Stilin, A.T. Holic, M. Liepe, T.I. O’Connell, J. Sears, V.D. Shemelin, J. Turco Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	The development of simpler, compact Superconducting RF (SRF) systems represents a new subject of research in accelerator science. These compact accelerators rely on advancements made to both Nb₃Sn SRF cavities and commercial cryocoolers, which together allow for the removal of liquid cryogenics from the system. This approach to SRF cavity operation, based on novel conduction cooling schemes, has the potential to drastically extend the range of application of SRF technology. By offering robust, non-expert, turn-key operation, such systems enable the use of SRF accelerators for industrial, medical, and small-scale science applications. This presentation will provide an overview of the significant progress being made at Cornell, Jefferson Lab, and Fermilab (FNAL), including stable cavity operation at 10 MV/m. It will also introduce the primary challenges of this new field and their potential solutions, along with an overview of the various applications which could benefit the most from this technology.

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	Slides TU1AA02 [4.683 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TU1AA02
About •	Received ※ 29 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 14 October 2022
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TU1AA03	R&D Towards High Gradient CW SRF Cavities	SRF, niobium, cryomodule, vacuum	295
	D. Bafia, P. Berrutti, B. Giaccone, A. Grassellino, D.V. Neuffer, S. Posen, A.S. Romanenko Fermilab, Batavia, Illinois, USA
	This talk will discuss Fermilab’s recent progress in the surface engineering of superconducting radio-frequency (SRF) cavities geared toward producing simultaneously high quality factors and high accelerating gradients in cryomodules. We investigate possible microscopic mechanisms that drive improved performance by carrying out sequential RF tests on cavities subjected to low temperature baking. We compare performance evolution to observations made with material science techniques and find correlations with material parameters. We also discuss other key advancements that enable high gradient operation in cryomodules.

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	Slides TU1AA03 [2.007 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TU1AA03
About •	Received ※ 20 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 16 October 2022
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TU1AA04	SWELL and Other SRF Split Cavity Development	HOM, GUI, vacuum, SRF	300
	F. Peauger CERN, Meyrin, Switzerland
	An innovative superconducting cavity topology has been recently proposed at CERN and at Lancaster University. It integrates longitudinal slots crossing perpendicularly the RF surface. The RF current lines run along the slots, inducing no perturbation of the accelerating mode. Thanks to this approach, the cavity can be built using halves or quadrants, which is well appropriate to precise manufacturing techniques. This configuration allows direct access to the RF surface, thus facilitating the surface preparation and thin film deposition process in the case of cavities based on Nb/Cu technology. The contact faces between the cavity parts are moved to the slots’ ends where the electromagnetic fields are extremely low, thus relaxing the constraints on the quality of the assembly joints. This paper covers the latest development of a 600 MHz slotted elliptical cavity called SWELL, which has been proposed as an alternative option for the FCC-ee RF system as well as a simplified SWELL version of a single cell 1.3 GHz elliptical cavity and a new 6 GHz split resonator made of two halves for superconducting thin film characterization. Acknowledgement of U. Van Rienen from Rostock University for the use of their GPU based workstations for RF simulations.

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	Slides TU1AA04 [4.217 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TU1AA04
About •	Received ※ 14 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 02 September 2022
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TU1AA06	Next-Generation Nb₃Sn Superconducting RF Cavities	SRF, accelerating-gradient, radio-frequency, superconducting-RF	305
	N.M. Verboncoeur, G. Gaitan, M. Liepe, R.D. Porter, L. Shpani, N.A. Stilin, Z. Sun Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Nb₃Sn currently is the most promising alternative material for next-generation, higher-performance SRF cavities. Significant recent progress has been made in further increasing efficiency, maximum field, and demonstrating readiness for first applications in actual accelerators. This paper will present an overview of worldwide recent progress in making this material a viable option for further accelerators.
	Slides TU1AA06 [6.559 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TU1AA06
About •	Received ※ 31 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 04 September 2022 — Issue date ※ 09 September 2022
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TU2AA02	SPIRAL2 Final Commissioning Results	MMI, linac, rfq, operation	314
	A.K. Orduz, P.-E. Bernaudin, M. Di Giacomo, R. Ferdinand, B. Jacquot, O. Kamalou, J.-M. Lagniel, G. Normand, A. Savalle GANIL, Caen, France D.U. Uriot CEA-DRF-IRFU, France
	The commissioning of SPIRAL2 was carried out in different steps and slots from 2014 to end 2021. In a first phase, the proton-deuteron and heavy ion sources, LEBT lines and RFQ were commissioned and validated with A/Q=1 up to 3 particles. The validation of the MEBT (between the RFQ and the linac, including the Single Bunch Selector), linac and HEBT lines (up to the beam dump and to the NFS experimental room) started on July 2019, when GANIL received the authorization to operate SPIRAL2. The linac tuning is now validated with H⁺, 4He2+ and D⁺ and nominal H⁺ and D⁺ beams were sent to NFS for physics experiments. The main results obtained during the commissioning stages and the strategy used by the commissioning team are presented.

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	Slides TU2AA02 [3.724 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TU2AA02
About •	Received ※ 24 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 02 September 2022
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TUPOJO03	Optimized Beam Optics Design of the MINERVA/MYRRHA Superconducting Proton Linac	linac, target, diagnostics, rfq	337
	U. Dorda, L. De Keukeleere SCK•CEN, Mol, Belgium F. Bouly, E. Froidefond LPSC, Grenoble Cedex, France E. Bouquerel, E.K. Traykov IPHC, Strasbourg Cedex 2, France L. Perrot Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
	The MYRRHA design for an accelerator driven system (ADS) is based on a 600 MeV superconducting proton linac. The first stage towards its realization is called MINERVA and was approved in 2018 to be constructed by SCK•CEN in Belgium. This 100 MeV linac, will serve as technology demonstrator for the high MYRRHA reliability requirements as well as driver for two independent target stations, one for radio-isotope research and production of radio-isotopes for medical purposes, the other one for fusion materials research. This contribution gives an overview of the latest accelerator machine physics design with a focus on the optimized medium (17 MeV) and high energy (100 MeV) beam transfer lines.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO03
About •	Received ※ 16 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 02 September 2022
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TUPOJO04	R&D for the Realization of a Very High Frequency Crossbar H-Mode Drift Tube Linac	DTL, linac, vacuum, coupling	341
	M. Heilmann, C. Zhang GSI, Darmstadt, Germany H. Podlech IAP, Frankfurt am Main, Germany
	A 704.4 MHz Crossbar H-mode (CH) drift tube linac has been proposed for performing a radio frequency jump at ß = 0.2. Up to now, the highest frequency of the constructed CH cavities is 360 MHz. Simulations have shown that the operation frequency for an H210-mode cavity can be up to ~800 MHz. At 704.4 MHz, the cavity dimensions become small, which bring challenges for many practical problems e.g. construction, vacuum pumping and RF coupling. This paper presents the performed R&D studies for the realization of such a very high frequency cavity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO04
About •	Received ※ 14 August 2022 — Revised ※ 19 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 31 August 2022
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TUPOJO05	Welding and Copper Plating Investigations on the FAIR Proton Linac	proton, linac, simulation, coupling	345
	A. Seibel, T. Dettinger, C.M. Kleffner, K. Knie, C. Will GSI, Darmstadt, Germany M.S. Breidt, H. Hähnel, U. Ratzinger IAP, Frankfurt am Main, Germany J. Egly PINK GmbH Vakuumtechnik, Wertheim, Germany
	A FAIR injector linac for the future FAIR facility is under construction. In order to meet the requirements for copper plating of the CH-cavities, a variety of tests with dummy cavities has been per-formed and compared to simulation. Further dummy cavities have been produced in order to improve the welding techniques. In addition, the results on 3d-printed stems with drift tubes will be presented.
	Poster TUPOJO05 [2.863 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO05
About •	Received ※ 08 August 2022 — Revised ※ 14 August 2022 — Accepted ※ 24 August 2022 — Issue date ※ 15 September 2022
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TUPOJO09	High Power RF Conditioning of the ESS DTL1	DTL, vacuum, controls, operation	356
	F. Grespan, C. Baltador, L. Bellan, D. Bortolato, M. Comunian, E. Fagotti, M.G. Giacchini, M. Montis, A. Palmieri, A. Pisent INFN/LNL, Legnaro (PD), Italy F. Grespan, B. Jones, L. Page, A.G. Sosa, E. Trachanas, R. Zeng ESS, Lund, Sweden D.J.P. Nicosia CERN, Meyrin, Switzerland
	The first tank of Drift Tube Linac (DTL) for the European Spallation Source ERIC (ESS), delivered by INFN, has been installed in the ESS tunnel in Summer 2021. The DTL-1 is designed to accelerate a 62.5 mA proton beam from 3.62 MeV up to 21 MeV. It consists of 61 accelerating gaps, alternate with 60 drift tubes equipped with Permanent Magnet Quadrupole (PMQ) in a FODO lattice. The remaining drift tubes are equipped with dipole correctors (steerers), beam position monitors (BPMs) or empty. The total length of the cavity is 7.6 m and it is stabilized by post couplers. Two waveguide couplers feed the DTL with the 2.2 MW of RF power required for beam operation, equally divided by RF power losses and beam power. This paper first presents the main systems required for the DTL conditioning. Then it summarizes the main steps and results of this high power RF conditioning done at ESS to prepare the DTL for the consequent beam commissioning.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO09
About •	Received ※ 15 August 2022 — Revised ※ 19 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 15 September 2022
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TUPOJO14	Status of Testing and Commissioning of the Medium Energy Beam Transport Line of the ESS Normal Conducting Linac	MEBT, linac, MMI, quadrupole	376
	A.G. Sosa, R.A. Baron, H. Danared, C.S. Derrez, E.M. Donegani, M. Eshraqi, V. Grishin, A. Jansson, M. Jensen, B. Jones, E. Laface, B. Lagoguez, Y. Levinsen, J.P.S. Martins, N. Milas, R. Miyamoto, D.J.P. Nicosia, D. Noll, D.C. Plostinar, T.J. Shea, R. Tarkeshian, C.A. Thomas, E. Trachanas, P.L. van Velze ESS, Lund, Sweden I. Bustinduy, A. Conde, D. Fernández-Cañoto, N. Garmendia, P.J. González, G. Harper, A. Kaftoosian, J. Martin, I. Mazkiaran, J.L. Muñoz, A.R. Páramo, S. Varnasseri, A.Z. Zugazaga ESS Bilbao, Zamudio, Spain
	The latest beam commissioning phase of the Normal Conducting Linac at ESS delivered a proton beam through the Medium Energy Beam Transport (MEBT) into the first Drift Tube Linac (DTL) tank. The probe beam in MEBT consisted of 3.6 MeV protons of <6 mA, <5 microseconds pulse length and 1 Hz repetition rate. Following the delivery of the components at ESS in Lund in June 2019, the commissioning phase with the MEBT was completed in July 2022. In March 2022, the maximum beam current of 62.5 mA was transported up to the MEBT Faraday cup. This proceeding focuses on the status of MEBT including magnets, buncher cavities, scrapers and beam diagnostics designed and tested in collaboration with ESS Bilbao.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO14
About •	Received ※ 13 August 2022 — Revised ※ 19 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 01 September 2022
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TUPOJO15	Commissioning of UKRI-STFC SRF Vertical Test and HPR Reprocessing Facility	SRF, MMI, cryogenics, vacuum	380
	M.D. Pendleton, A.E.T. Akintola, R.K. Buckley, G. Collier, K.D. Dumbell, M.J. Ellis, S. Hitchen, P.C. Hornickel, G. Hughes, C.R. Jenkins, A.J. May, P.A. McIntosh, K.J. Middleman, A.J. Moss, S.M. Pattalwar, J.O.W. Poynton, P.A. Smith, A.E. Wheelhouse, S. Wilde STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom G. Jones, M. Lowe, D.A. Mason, G. Miller, C. Mills, J. Mutch, A. Oates, J.T.G. Wilson STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	Mark Pendleton, et al. The UK’s first and only vertical test facility and associated cleanroom reprocessing suite has been developed, commissioned, and entered steady-state operations at the UKRI-STFC Daresbury Laboratory. The facility is capable of 2 K testing of 3 jacketed SRF cavities in a horizontal configuration per 2-week test cycle. We report on the associated cryogenic, RF, UHV, mechanical, cleanroom, and HPR infrastructure. SRF cavity workflows have been developed to meet the requirements of the ESS high beta cavity project within a newly developed quality management system, SuraBee, in accordance with ISO9001. To support standardisation of measurements across the collaboration, reference cavities have been measured for cross-reference between CEA, DESY, and UKRI-STFC. We further report on commissioning objectives, observations, and continuous improvement activities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO15
About •	Received ※ 24 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 05 September 2022 — Issue date ※ 08 September 2022
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TUPOJO17	High Efficiency High Power Resonant Cavity Amplifier For PIP-II	coupling, impedance, network, electron	384
	R.E. Simpson, N. Butler, D.B. Cope, M.P.J. Gaudreau, M.K. Kempkes Diversified Technologies, Inc., Bedford, Massachusetts, USA
	An advanced high-power, high power density, solid state power amplifier (SSPA) was developed to replace Vacuum Electron Devices (VEDs). Diversified Technologies, Inc. (DTI) developed and integrated a resonant-cavity combiner with solid state amplifiers for the Proton Improvement Plan-II (PIP-II) at Fermilab. The architecture combines the power of N-many RF power transistors into a single resonant cavity that are surface-mounted and -cooled. The system is designed so that failure of individual transistors has negligible performance impact. Due to the electrical and mechanical simplicity, maintenance and logistics are simplified. DTI demonstrated the basic feasibility of a 50-100 kW class amplifier resonant cavity combiner system at 650 MHz. A single-cavity system reached 15 kW at 66% power-added efficiency with ten of 12 slots filled on only 1 of 2 cavities faces. The system further demonstrated the expected graceful degradation; an intermittent fault occurred on 1 of the 10 modules and the only observable effect was a reduction in output power to 13.3 kW with a slight reduction in efficiency. Combining of multiple cavities was also demonstrated at low power.
	Poster TUPOJO17 [0.790 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO17
About •	Received ※ 16 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 15 September 2022
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TUPOJO18	Cavity Qualification and Production Update for SNS-PPU Cryomodules at Jefferson Lab	cryomodule, proton, SRF, neutron	387
	P. Dhakal, E. Daly, J.F. Fischer, N.A. Huque JLab, Newport News, Virginia, USA M.P. Howell ORNL, Oak Ridge, Tennessee, USA J.D. Mammosser ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: This manuscript has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The Proton Power Upgrade (PPU) project at Oak Ridge National Lab’s Spallation Neutron Source (SNS) currently being constructed will double the proton beam power capability from 1.4 to 2.8 MW by adding seven cryomodules, each containing four six-cell high-beta (β = 0.81) superconducting radio frequency cavities. Research Instruments, located in Germany, built and processed the cavities at the vendor site, including electropolishing as the final active chemistry step. Twenty-eight cavities for seven cryomodules and an additional four cavities for a spare cryomodules were delivered to Jefferson Lab and first qualification tests were completed on all cavities as received from the vendor. The performance largely exceeded the requirements on quality factor and accelerating gradient. Here we present the status of initial cavity qualification tests, rework on unqualified cavities and final cavity qualification with helium vessel prior to installation in cryomodules. In addition, an update on cryomodule production is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO18
About •	Received ※ 23 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 09 September 2022
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TUPOJO22	Progress of PIP-II Activities at IJCLab	HOM, SRF, experiment, niobium	402
	P. Duchesne, N. Gandolfo, D. Le Dréan, D. Longuevergne, R. Martret, T. Pépin-Donat, F. Rabehasy, S. Roset, L.M. Vogt Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France P. Berrutti, M. Parise, D. Passarelli Fermilab, Batavia, Illinois, USA
	Since 2018, IJCLab is involved in PIP-II project on the design and development of accelerator components for the SSR2 (Single Spoke Resonator type 2) section of the superconducting linac. First pre-production components have been fabricated, surface processing and cavity qualification in vertical cryostat are on-going. IJCLab has upgraded its facilities by developing a new set-up to perform rotational BCP. The progress of all processing and testing activities for PIP-II project will be reported and, in particular, a dedicated study to qualify removal uniformity compared to static BCP will be presented.
	Poster TUPOJO22 [1.997 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO22
About •	Received ※ 23 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 01 September 2022
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TUPOJO23	Accelerated Lifetime Test of Spoke Cavity Cold Tuning Systems for Myrrha	cryomodule, operation, SRF, vacuum	406
	N. Gandolfo, S. Blivet, F. Chatelet, V. Delpech, D. Le Dréan, G. Mavilla, M. Pierens, H. Saugnac Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
	Within the framework of MINERVA, the first Phase of MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) project, IN2P3 labs are in charge of the developments of several accelerator elements. Among those, a fully equipped Spoke cryomodule prototype was constructed, it integrates two superconducting single spoke cavities operating at 2K, the RF power couplers and the associated cold tuning systems. The extreme reliability specified for this project motivated to conduct ALT (Accelerated Lifetime Test) on two extra cold tuning systems in cryomodule like environment. Thus, by gathering information from experimental data, many aspects can be enhanced like maintenance plan consolidation, determination of aging indicators and design optimization of the whole system and its sub components. This paper describes the complete ALT process from the studying elements and the test environment design, to the experimental results and findings.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO23
About •	Received ※ 15 August 2022 — Revised ※ 17 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 02 September 2022
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TUPOPA05	RFQ Performance During RF Conditioning and Beam Commissioning at ESS	rfq, beam-loading, multipactoring, MMI	418
	R. Zeng, G.S. Fedel, B. Jones, R. Miyamoto, D.J.P. Nicosia, D. Noll, A.G. Sosa, A.M. Svensson, E. Trachanas ESS, Lund, Sweden M. Baudrier CEA-DRF-IRFU, France A.C. Chauveau, M.J. Desmons, P. Hamel, O. Piquet CEA-IRFU, Gif-sur-Yvette, France F. Grespan INFN/LNL, Legnaro (PD), Italy
	RFQ at ESS has been successfully gone through RF conditioning, RF re-conditioning and low duty cycle beam commissioning. RFQ fulfills required functions and overall performance is satisfactory. RF conditioning, three RF re-conditionings after LEBT intervention and beam commissioning will be reported and RFQ performance during these periods will be described. RFQ performance in a large extent is reflected by dynamics and interactions between RF, cavity and beam. Thanks to advanced hardware capabilities and intelligent software intelligence, observation of those dynamics and interactions are done in detailed level. Analysis of those dynamics and interaction will be introduced. Some techniques to deal with challenges resulted from those dynamics and interactions will also be discussed.
	Poster TUPOPA05 [25.281 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA05
About •	Received ※ 18 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 05 September 2022
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TUPOPA11	Compact Proton Accelerator in UHF Band At KAHVELab	rfq, proton, vacuum, quadrupole	434
	S. Esen, A. Adiguzel, O. Kocer, S. Oz Istanbul University, Istanbul, Turkey A. Caglar YTU, Istanbul, Turkey E. Celebi, E.V. Ozcan Bogazici University, Bebek / Istanbul, Turkey E. Celebi IBU, Istanbul, Turkey A.K. Karatay, F. Yaman, Ö.H. Yilmaz IZTECH, Izmir, Turkey U. Kaya Istinye University, Institute of Sciences, Istanbul, Turkey A. Kilicgedik Marmara University, Istanbul, Turkey G. Türemen Turkish Atomic Energy Authority, Ankara, Turkey G. Unel UCI, Irvine, California, USA
	Funding: This project are supported by TUBITAK Project no: 118E838 Proton Test Beam at KahveLAB (Kandilli Detector, Accelerator and Instrumentation Laboratory) project aims to design and produce a radio frequency quadrupole (RFQ) operating at 800 MHz in Istanbul, Turkey using the local resources. The beamline consists of a proton source, a low energy beam transport (LEBT) line including the beam diagnostic section, and the RFQ cavity itself. This RFQ is a 4-vane, 1-meter-long cavity to accelerate the 20 keV beam extracted from the plasma ion source to 2 MeV. Its engineering prototype is already produced and subjected to mechanical, low-power RF, and vacuum tests. In this poster, the results of the first test production, especially the bead-pull test setup will be discussed.
	Poster TUPOPA11 [16.128 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA11
About •	Received ※ 21 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 12 September 2022 — Issue date ※ 26 September 2022
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TUPOPA15	Multipactor Studies: Simulations and Measurements on the RF Coaxial Resonator Test Bench	multipactoring, electron, simulation, experiment	445
	Y. Gómez Martínez, J. Angot, M.A. Baylac, T. Cabanel, M. Meyer LPSC, Grenoble Cedex, France D. Longuevergne, G. Sattonnay Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
	Multipactor is an undesired phenomenon triggered by electromagnetic fields in accelerator components and more specifically in RF structures, such as accelerating cavities and power couplers, and may lead to Electron Cloud build up in beam tubes. The accelerator group at LPSC has developed an experimental setup dedicated to multipactor studies. It consists in a coaxial resonator, tunable and operational between 100 MHz and 1 GHz. It allows to characterize under real conditions the efficiency of surface treatment mitigation processes (coatings, cleaning procedures) at room temperature. This paper presents the experimental measurements performed with this setup confronted to simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA15
About •	Received ※ 12 August 2022 — Revised ※ 30 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 16 September 2022
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TUPOPA16	Complete Study of the Multipactor Phenomenon for the MYRRHA 80 kW CW RF Couplers	multipactoring, electron, simulation, linac	448
	Y. Gómez Martínez, P.-O. Dumont, M. Meyer LPSC, Grenoble Cedex, France P. Duchesne, C. Joly, W. Kaabi Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
	MYRRHA [1] (Multi Purpose Hybrid Reactor for High Tech Applications) is an Accelerator Driven System (ADS) project. Its superconducting linac will provide a 600 MeV - 4 mA proton beam. The first project phase based on a 100 MeV linac is launched. The Radio-Frequency (RF) couplers have been designed to handle 80 kW CW (Continuous Wave) at 352.2 MHz. This paper describes the multipacting studies on couplers.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA16
About •	Received ※ 12 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 05 September 2022
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TUPOPA18	Test and Commissioning of the HELIAC Power Coupler	operation, cryomodule, multipactoring, heavy-ion	454
	J. List, K. Aulenbacher, W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, M. Miski-Oglu, S. Yaramyshev HIM, Mainz, Germany K. Aulenbacher, W.A. Barth, F.D. Dziuba, S. Lauber, J. List KPH, Mainz, Germany K. Aulenbacher, W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu, S. Yaramyshev GSI, Darmstadt, Germany T. Conrad, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany
	The superconducting continuous wave (cw) heavy ion HElmholtz LInear ACcelerator (HELIAC) is intended to be built at GSI in Darmstadt. With its high average beam current and repetition rate, the HELIAC is designed to fulfill the requirements of the super heavy element (SHE) research user program and the material sciences community at GSI. The accelerating cavities are of the superconducting Crossbar H-mode (CH) type, developed by GUF. Within the Advanced Demonstrator project, the first cryomodule, consisting of four cavities is scheduled for commissioning with beam in 2023. The former RF power couplers introduced a high heat input into the cryostat. Therefore, the coupler is redesigned at HIM in order to not only reduce the heat input but to provide an overall improved power coupler for the HELIAC. It is designed for maximal power of 5 kW cw at the frequency of 216.816 MHz. A prototype has been tested and commissioned recently. This includes several RF-tests at room temperature and in cryogenic environments. The results of these tests will be presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA18
About •	Received ※ 20 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 01 September 2022
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TUPOPA24	Design of an X-Band Bunching and Accelerating System for AWAKE Run 2	acceleration, electron, bunching, gun	458
	J.M. Arnesano, S. Döbert CERN, Meyrin, Switzerland
	The AWAKE experiment at CERN demonstrated in its Run 1 that it is possible to accelerate electrons in plasma wakefields driven by a self-modulated proton bunch. In Run2, AWAKE aims to increase the accelerating gradient in the plasma even further and demonstrate beam quality in order to be ready for high-energy physics experiments. In this framework, a new electron injector, consisting of an S-band RF-gun and a subsequent X-band bunching and accelerating section, capable of producing very short bunches with a small emittance, has been designed. In this paper, two different configurations of the X-band section and their corresponding high-power distribution systems are presented. The first one consists of three identical cavities to bunch and accelerate the beam while the second one uses a separate short structure for velocity bunching followed by three long, pure accelerating structures. A discussion of the strengths and weaknesses of each configuration is carried out and beam dynamics aspects are analyzed. Finally the X-Band power distribution systems are described with particular attention to the choice of the klystron, the pulse compression system and the waveguide distribution.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA24
About •	Received ※ 12 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 16 September 2022
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TUPOPA25	Design, Manufacturing, Assembly, Testing, and Lessons Learned of the Prototype 650 MHz Couplers	vacuum, SRF, cryomodule, multipactoring	462
	J. Helsper, S.K. Chandrasekaran, F. Furuta, B.M. Hanna, S. Kazakov, J.P. Ozelis, K.S. Premo, N. Solyak, G. Wu Fermilab, Batavia, Illinois, USA
	Funding: Work supported, in part, by the U.S. Department of Energy, Office of Science, Office of High Energy Physics, under U.S. DOE Contract No. DE-AC02-07CH11359. Six 650 MHz high-power couplers will be integrated into the prototype High Beta 650 MHz (HB650) cryomodule for the PIP-II project at Fermilab. The design of the coupler is described, including design optimizations from the previous generation. This paper then describes the coupler life-cycle, including manufacturing, assembly, testing, conditioning and the lessons learned at each stage.
	Poster TUPOPA25 [2.695 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA25
About •	Received ※ 24 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 02 September 2022
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TUPOPA27	Conceptual Analysis of a Compact High Efficiency Klystron	klystron, bunching, wiggler, focusing	466
	J.P. Edelen, S.D. Webb RadiaSoft LLC, Boulder, Colorado, USA K.E. Nichols LANL, Los Alamos, New Mexico, USA
	Traditional klystron efficiencies are limited by the output electron beam harmonic current and energy spread. Increasing the amount of harmonic current produced in the klystron requires increasing the velocity bunching in the input cavity. Additional cavities may be used to improve the bunching, however they do so at additional cost and space requirements for the klystron. Moreover, at higher currents space charge counteracts this velocity bunching reducing the amount of harmonic current that can be produced. Our concept resolves these challenges by employing a new type of high-efficiency, multi-beam klystron. Our design consists of a single two-frequency input cavity, a wiggler, and an output cavity. The two-frequency input cavity approximates a linear function in time thereby increasing the harmonic content of the beam, while the wiggler provides strong longitudinal focusing to mitigate the effects of space charge. In this paper we provide the theoretical foundation for our design and present initial numerical calculations showing improved bunching from the harmonic mode and the wiggler.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA27
About •	Received ※ 14 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 31 August 2022
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TUPOPA30	Innovative Magnetron Power Sources for SRF Linacs	cathode, electron, simulation, power-supply	473
	M. Popovic, M.A. Cummings, A. Dudas, R.P. Johnson, R.R. Lentz, M.L. Neubauer, T. Wynn Muons, Inc, Illinois, USA T. Blassick, J.K. Wessel Richardson Electronics Ltd, Lafox, Illinois, USA K. Jordan, R.A. Rimmer, H. Wang JLab, Newport News, Virginia, USA
	Funding: Supported in part by US Department of Energy Nuclear Physics SBIR Grant DE-SC0022484 Magnetron RF power sources for single cavities can cost much less and operate at much higher efficiency than klystrons, but they do not have the phase and amplitude control, or the lifetime, needed to drive SRF cavities for superconducting particle accelerators. Existing magnetrons that are typically used to study methods of control or lifetime improvements for SRF accelerators are built for much different applications such as kitchen microwave ovens (1kW, 2.45 GHz) or industrial heating (100 kW, 915 MHz). Muons, Inc. is working with Richardson Electronics LLC to develop fast and flexible manufacturing techniques to allow many ideas to be tested for construction variations that enable new phase and amplitude injection locking control methods, longer lifetime, and inexpensive refurbishing resulting in the lowest possible life-cycle costs. A magnetron suitable for 1497 MHz klystron replacements at Jefferson Lab has been designed, constructed, and tested.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA30
About •	Received ※ 16 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022
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TUPOGE01	Commissioning of the VECC Cryomodule	solenoid, MMI, ISAC, vacuum	476
	Z.Y. Yao, R. Bjarnason, J. Cheung, K. Fong, J.J. Keir, D. Kishi, S. Kiy, P. Kolb, D. Lang, R.E. Laxdal, B. Matheson, R.S. Sekhon, B.S. Waraich, Q. Zheng, V. Zvyagintsev TRIUMF, Vancouver, Canada
	A quarter-wave resonator (QWR) cryomodule was designed and assembled at TRIUMF for the energy upgrade of the VECC ISOL-RIB facility to boost radioactive isotopes from 1MeV/u to 2MeV/u. The top loading cryomodule was chosen based on the ISAC-II low energy section design, consisting of four superconducting QWRs and one superconducting solenoid. The major change from ISAC-II concept is separating the RF space vacuum from the isolation vacuum. The cryogenic commissioning was recently completed. The cold mass alignments and the cryogenic heat loads were measured. The cavity performance was qualified in both test regime and operating regime. The cavity degradations caused by magnetic pollution from solenoid and the recovery procedure were verified. This paper will report the detailed results of the commissioning.

Paper

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Other Keywords

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MO2AA04

Electron Ion Collider Strong Hadron Cooling Injector and ERL

electron, linac, emittance, hadron

7

E. Wang, W.F. Bergan, F.J. Willeke
BNL, Upton, New York, USA
S.V. Benson, K.E. Deitrick
JLab, Newport News, Virginia, USA
D. Douglas
Douglas Consulting, York, Virginia, USA
C.M. Gulliford
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
C.E. Mayes, N.W. Taylor
Xelera Research LLC, Ithaca, New York, USA
J. Qiang
LBNL, Berkeley, California, USA

Funding: The work is supported by Brookhaven Science Associates, LLC under Contract No. DESC0012704 with the U.S. Department of Energy.
Intra-beam Scattering (IBS) and other diffusion mechanisms in the EIC Hadron Storage Ring (HSR) degrade the beam emittances during a store, with growth times of about 2 hours at the nominal proton energies of 275GeV, 100 GeV, and 41 GeV. Strong Hadron Cooling (SHC) can maintain good hadron beam quality and high luminosity during long collision stores. A novel cooling method ’ Coherent electron Cooling (CeC) ’ is chosen as the baseline SHC method, due to its high cooling rates. An Energy Recovery Linac (ERL) is used to deliver an intense high-quality electron beam for cooling. In this paper, we discuss the beam requirements for SHC-CeC and describe the current status of the injector and ERL designs. Two designs of injector and ERL will be presented: one for dedicated SHC and another one for SHC with precooler.

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Slides MO2AA04 [4.436 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MO2AA04

About •

Received ※ 23 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 27 August 2022 — Issue date ※ 31 August 2022

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MO1PA01

Beam Commissioning and Integrated Test of the PIP-II Injector Test Facility

MMI, cryomodule, operation, MEBT

13

E. Pozdeyev, R. Andrews, C.M. Baffes, M. Ball, C. Boffo, R. Campos, J.-P. Carneiro, B.E. Chase, A.Z. Chen, D.J. Crawford, J. Czajkowski, N. Eddy, M. El Baz, M.G. Geelhoed, V.M. Grzelak, P.M. Hanlet, B.M. Hanna, B.J. Hansen, E.R. Harms, B.F. Harrison, M.A. Ibrahim, K.R. Kendziora, M.J. Kucera, D.D. Lambert, J.R. Leibfritz, P. Lyalyutskyy, J.N. Makara, H. Maniar, L. Merminga, R. Neswold, D.J. Nicklaus, J.P. Ozelis, D. Passarelli, N. Patel, D.W. Peterson, L.R. Prost, G.W. Saewert, A. Saini, V.E. Scarpine, A.V. Shemyakin, J. Steimel, A.I. Sukhanov, P. Varghese, R. Wang, A. Warner, G. Wu, R.M. Zifko
Fermilab, Batavia, Illinois, USA
V.K. Mishra, M.M. Pande, K. Singh, Vikas. Teotia
BARC, Mumbai, India

The PIP-II Injector Test (PIP2IT) facility is a near-complete low energy portion of the Superconducting PIP-II linac driver. PIP2IT comprises the warm front end and the first two PIP-II superconducting cryomodules. PIP2IT is designed to accelerate a 2 mA H⁻ beam to an energy of 20 MeV. The facility serves as a testbed for a number of advanced technologies required to operate PIP-II and provides an opportunity to gain experience with commissioning of the superconducting linac, significantly reducing project technical risks. Some PIP2IT components are contributions from international partners, who also lend their expertise to the accelerator project. The project has been successfully commissioned with the beam in 2021, demonstrating the performance required for the LBNF/DUNE. In this paper, we describe the facility and its critical systems. We discuss our experience with the integrated testing and beam commissioning of PIP2IT, and present commissioning results. This important milestone ushers in a new era at Fermilab of proton beam delivery using superconducting radio-frequency accelerators.

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Slides MO1PA01 [2.714 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MO1PA01

About •

Received ※ 16 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 13 October 2022

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MOPOJO03

HELEN: A Linear Collider Based on Advanced SRF Technology

collider, SRF, linear-collider, linac

31

S.A. Belomestnykh, P.C. Bhat, M. Checchin, A. Grassellino, M. Martinello, S. Nagaitsev, S. Posen, A.S. Romanenko, V.D. Shiltsev, A. Valishev, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA
S.A. Belomestnykh
Stony Brook University, Stony Brook, USA
H. Padamsee
Cornell University, Ithaca, New York, USA

Funding: Work supported by the Fermi National Accelerator Laboratory, managed and operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
This paper discusses recently proposed Higgs-Energy LEptoN (HELEN) e+e’ linear collider based on advances superconducting radio frequency technology. The collider offers cost and AC power savings, smaller footprint (relative to the ILC), and could be built at Fermilab with an Interaction Region within the site boundaries. After the initial physics run at 250 GeV, the collider could be upgraded either to higher luminosity or to higher (up to 500 GeV) energies.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO03

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Received ※ 24 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 04 September 2022 — Issue date ※ 15 September 2022

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MOPOJO08

RF Design, Optimization and Multiphysics Study of a β = 1, 1.3 GHz Single Cell Accelerating Cavity for High-Intensity Compact Superconducting Electron Accelerator (HICSEA)

multipactoring, electron, HOM, accelerating-gradient

41

M. Meena, A. Pathak, R. Varma
IIT Mumbai, Mumbai, India

High-energy electron accelerators have been used in water purification for several years. They are very effective for the removal of complex impurities. This study aims to design a superconducting electron beam accelerator with an output energy of 1 MeV and beam power of 40 kW for wastewater treatment. A 1.3 GHz single cell elliptic cavity with β = 1 was designed and optimized for TM010 mode and an accelerating gradient of 15 MV/m. For the optimized cavity, the RF parameters, namely, R/Q, transit time factor and geometry factor (G) were found to be 174.93 ohm, 0.67 and 276 ohm, respectively. Multiphysics studies showed that the value of R/Q for fundamental accelerating mode was 174.93 ohm. It was much higher than that of other modes, thus, HOM coupler is not required for the system. The Lorentz force detuning coefficient after stiffening the cavity iris, and the temperature rise due to the RF surface losses were found to be 0.20 Hz/(MV/m)2 and 0.085 K, respectively. It is also observed that there is no occurrence of multipacting for the designed accelerating gradient.

Poster MOPOJO08 [1.584 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO08

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Received ※ 24 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 05 September 2022

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MOPOJO09

A Compact Inverse Compton Scattering Source Based on X-Band Technology and Cavity-Enhanced High Average Power Ultrafast Lasers

photon, electron, laser, linac

44

A. Latina, R. Corsini, L.A. Dyks, E. Granados, A. Grudiev, V. Musat, S. Stapnes, W. Wuensch
CERN, Meyrin, Switzerland
E. Cormier
CELIA, Talence, France
L.A. Dyks
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
G. Santarelli
ILE, Palaiseau Cedex, France

A high-pulse-current injector followed by a short high-gradient X-band linac is considered as a driver for a compact Inverse Compton Scattering source. We show that using a high-power ultrashort pulse laser operating in burst mode and a Fabry-Pérot enhancement cavity, X-rays with flux values over 10¹³ ph/s and photon energies up to MeV are achievable. The resulting high-intensity and high-energy X-rays allow for various applications, including cancer therapy, tomography, and nuclear waste management. A preliminary conceptual design of such a compact ICS source is presented, together with simulations of the expected performance.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO09

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Received ※ 19 August 2022 — Revised ※ 30 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 06 September 2022

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MOPOJO11

Challenges for High-Energy X-Ray Security Screening Linacs

linac, electron, detector, photon

50

M. Jenkins, J. Ollier, M.G. Procter
Rapiscan Systems Ltd, Stoke-on-Trent, United Kingdom

X-ray based Cargo and Vehicle Inspection (CVI) systems are used for security and customs inspections at a variety of locations. To provide the maximum flexibility many users require mobile CVI systems to allow vehicles to be screened efficiently for threats and contraband. The need for mobile systems means that the linear accelerator, and ancillary systems, used to generate the x-rays must be compact, rugged, and reliable. These systems must meet image performance tests specified by American National Standards Institute (ANSI) and the International Electrotechnical Commission (IEC). The IEC also defines a standard for material discrimination. The requirements of these standards mean that the x-ray output produced by the linac needs to be consistent during and between scans, with the stability and repeatability of the output being critical. The tolerances on the linac output to meet the performance standards combined with the need for a compact system gives an unusual challenge for the linac design. A review of how different stability measures impact the performance tests is presented. This is compared to current technologies and possible future linacs used for mobile CVI systems.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO11

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Received ※ 24 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022

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MOPOJO12

Design of a Compact Linac for High Average Power Radiotherapy

linac, coupling, GUI, gun

53

C.D. Nantista, G.B. Bowden, Z. Li, M. Shumail, S.G. Tantawi
SLAC, Menlo Park, California, USA
B.W. Loo
Stanford University, Stanford, California, USA

We present the design of a compact, 10 MeV, 300 mA pulsed X-band linac developed for medical application. The layout, <1 m including gun, buncher, capture section and current monitor, is of a recent configuration in which the 36 main linac cavities are individually fed in parallel through side waveguide manifolds, allowing for split fabrication. Initially destined for experimental study of FLASH irradiation of mouse tumors, the design was developed as a prototype for realization of a PHASER cancer treatment machine, in which multiple linacs, powered sequentially from a common RF source, are to provide rapid treatment to patients from multiple directions without mechanical movement, delivering dosage on a time scale that essentially freezes the patient. In this paper, we focus on the RF design, beam capture optimization, mechanical design and fabrication of the linac itself, deferring discussion of other important aspects such as window and target design, experimental specification setting, radiation shielding and operations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO12

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Received ※ 22 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 06 September 2022

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MOPOJO16

Cryogenic Accelerator Design for Compact Very High Energy Electron Therapy

linac, coupling, distributed, electron

62

E.J.C. Snively, V. Borzenets, G.B. Bowden, A.K. Krasnykh, Z. Li, C.D. Nantista, M. Oriunno, M. Shumail, S.G. Tantawi
SLAC, Menlo Park, California, USA
B.W. Loo
Stanford University, Stanford, California, USA

Funding: This research has been supported by the U.S. Department of Energy (DOE) under Contract No. DE-C02-76SF00515.
We report on the development of a cryogenic X-band (11.424 GHz) accelerator to provide electron beams for Very High Energy Electron therapy. The distributed coupling linac is designed with a 135° phase advance, capable of producing a 100 MeV/m accelerating gradient in a one-meter structure using only 19 MW when operating at 77 K. This peak power will be achieved through pulse compression of a 5-8 MW few-µs pulse, ensuring compatibility with a commercial power source. We present designs of the cryogenic linac and power distribution system, as well as a room temperature pulse compressor using the HE11 mode in a corrugated cavity. We discuss scaling this compact and economical design into a 16 linac array that can achieve FLASH dose rates (> 40 Gy/s) while eliminating the downtime associated with gantry motion.

Slides MOPOJO16 [1.320 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO16

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Received ※ 14 August 2022 — Revised ※ 18 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 26 September 2022

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MOPOJO17

Design and Optimization of a 100 kV DC Thermionic Electron Gun and Transport Channel for a 1.3 GHz High Intensity Compact Superconducting Electron Accelerator (HICSEA)

electron, solenoid, gun, cathode

65

P. Nama, A. Pathak, R. Varma
IIT Mumbai, Mumbai, India

Here we present, the design and optimization of a 100 kV DC thermionic electron gun, and a transport channel that provides transverse focusing through a normal conducting solenoid and longitudinal bunching with the help of a single gap buncher for a 1.3 GHz, 40 kW, 1 MeV superconducting electron accelerator. The accelerator is proposed to treat various contaminants present in potable water resources. A 100 kV thermionic electron gun with LaB6 as its cathode material was intended to extract a maximum beam current of 500 mA. To minimize beam emittance, gun geometry i.e. cathode radius, and height and radius of the focusing electrode are optimized. The minimal obtained emittance at the gun exit is 0.3 mm.mrad. A normal conducting focusing solenoid with an iron encasing is designed and optimized to match and transport the beam from gun exit to the superconducting cavity. Finally, a 1.3 GHz ELBE type buncher is designed and optimized to bunch the electron beam for further acceleration.

Slides MOPOJO17 [1.268 MB]

Poster MOPOJO17 [0.813 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO17

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Received ※ 23 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 27 August 2022 — Issue date ※ 31 August 2022

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MOPOJO19

Programmable SLED System for Single Bunch and Multibunch Linac Operation

klystron, linac, operation, LLRF

73

C. Christou, P. Gu, A. Tropp
DLS, Oxfordshire, United Kingdom

The Diamond Light Source pre-injector linac generates single bunch and multibunch 100 MeV electron beams for top-up and fill of the storage ring. The linac is powered by two high-power 3 GHz klystrons, and both klystrons are required for reliable injection into the booster and storage ring. In order to introduce redundancy, a SLED pulse compression cavity has been installed so that the linac can operate from just one klystron, with the second klystron held as a standby. A simple phase flip can be used to generate a high-power transient RF spike, suitable for single bunch linac operation, and a programmable amplitude and phase drive profile can be specified to generate a constant-power klystron output suitable for multibunch operation. Details are presented of design, installation and high-power operation of the SLED system, and the ability to generate a long pulse, including corrections for klystron nonlinearity and deviations from modulator flat-top, is demonstrated.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO19

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Received ※ 09 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 08 September 2022

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MOPOPA02

Identification of the Mechanical Dynamics of the Superconducting Radio-Frequency Cavities for the European XFEL CW Upgrade

controls, FEL, SRF, experiment

76

W.H. Syed, A. Bellandi, J. Branlard, A. Eichler
DESY, Hamburg, Germany

The European X-Ray Free-Electron Laser (EuXFEL) is to-date the largest X-ray research facility around the world which spans over 3.4 km. EuXFEL is currently being operated in a pulsed mode with a repetition rate of 10Hz. One upgrade scenario consists of operating the EuXFEL also in a Continuous-Wave (CW) mode of operation to improve the quality of experiments. This upgrade brings new challenges and requires new algorithms to deal with controlling a stable accelerating field inside the Superconducting Radiofrequency (SRF) accelerating cavities and keeping them on resonance in this new mode of operation. The purpose of this research work is to identify the mechanical dynamics of the cavities which will facilitate the development of the resonance controller for the CW upgrade. To this extent, experiments were conducted at a test bench. For the first time, in this work, two different types of spectrally rich excitation signals: multi-sine and stepped-sine are used to excite the mechanical dynamics of the cavities using the piezo actuator. After the analysis of experimental data, mechanical modes are successfully identified and will be used to design the controller.

Poster MOPOPA02 [0.687 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA02

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Received ※ 23 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 26 August 2022 — Issue date ※ 01 September 2022

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MOPOPA03

Beam-Transient-Based LLRF Voltage Signal Calibration for the European XFEL

FEL, LLRF, linac, operation

80

N. Walker, V. Ayvazyan, J. Branlard, S. Pfeiffer, Ch. Schmidt
DESY, Hamburg, Germany

The European XFEL linac consists of 25 superconducting RF (SRF) stations. With the exception of the first station which is part of the injector, each station comprises 32 1.3-GHz SRF TESLA cavities, driven by a single 10-MW klystron. A sophisticated state-of-the-art low-level RF (LLRF) system maintains the complex vector sum of each RF station. Monitoring and maintaining the calibration of the cavity electric field (gradient) probe signals has proven critical in achieving the maximum energy performance and availability of the SRF linac. Since there are no dedicated diagnostics for cross-checking calibration of the LLRF system, a procedure has been implemented based on simultaneously measuring the beam transient in open-loop operation of all cavities. Based on methods originally developed at FLASH, the European XFEL procedure makes use of automation and the XFEL LLRF DAQ system to provide a robust and relatively fast (minutes) way of extracting the transient data, and is now routinely scheduled once per week. In this paper, we will report on the background, implementation, analysis methods, typical results, and their subsequent application for machine operation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA03

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Received ※ 13 August 2022 — Revised ※ 23 August 2022 — Accepted ※ 14 September 2022 — Issue date ※ 27 September 2022

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MOPOPA13

200 MV Record Voltage of vCM and LCLS-II-HE Cryomodules Production Start Fermilab

cryomodule, SRF, vacuum, plasma

95

T.T. Arkan, D. Bafia, D.J. Bice, J.N. Blowers, A.T. Cravatta, B. Giaccone, C.J. Grimm, B.D. Hartsell, J.A. Kaluzny, M. Martinello, T.H. Nicol, Y.M. Orlov, S. Posen
Fermilab, Batavia, Illinois, USA
M. Checchin
SLAC, Menlo Park, California, USA

Funding: Department of Energy
The Linac Coherent Light Source (LCLS) is an X-ray science facility at SLAC National Accelerator Laboratory. The LCLS-II project (an upgrade to LCLS) is in the commissioning phase; the LCLS-II-HE (High Energy) project is another upgrade to the facility, enabling higher energy operation. An electron beam is accelerated using superconducting radio frequency (SRF) cavities built into cryomodules. It is planned to build 24 1.3 GHz standard cryomodules and 1 1.3 GHz single-cavity Buncher Capture Cavity (BCC) cryomodule for the LCLS-II-HE project. Fourteen of these standard cryomodules and one BCC are planned to be assembled and tested at Fermilab. Procurements for standard cryomodule components are nearing completion. The first LCLS-II-HE cryomodule, referred to as the verification cryomodule (vCM) was assembled and tested at Fermilab. Fermilab has completed the assembly of the second cryomodule. This paper presents LCLS-II-HE cryomodule production status at Fermilab, emphasizing the changes done based on the successes, challenges, mitigations, and lessons learned from LCLS-II; validation of the changes with the excellent vCM results.

Poster MOPOPA13 [1.975 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA13

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Received ※ 10 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 09 September 2022

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MOPOPA15

Three Years of Operation of the SPIRAL2 SC LINAC- RF Feedback

linac, LLRF, controls, operation

98

M. Di Giacomo, M. Aburas, P.-E. Bernaudin, O. Delahaye, A. Dubosq, A. Ghribi, J.-M. Lagniel, J.F. Leyge, G. Normand, A.K. Orduz, F. Pillon, L. Valentin
GANIL, Caen, France
F. Bouly
LPSC, Grenoble Cedex, France
S. Sube
CEA-DRF-IRFU, France

The superconducting LINAC of SPIRAL2 at the GANIL facility has been in operation since October 2019. The accelerator uses 12 low beta and 14 high beta supercon-ducting quarter wave cavities, cooled at 4°K, working at 88 MHz. The cavities are operated at a nominal gradient of 6.5 MV/m and are independently powered by a LLRF and a solid-state amplifier, protected by a circulator. Pro-ton and deuteron beam currents can reach 5 mA and beam loading perturbation is particularly strong on the first cavities, as they are operated at field levels much lower than the nominal one. This paper presents a feedback after three years of oper-ation, focuses on the RF issues, describing problems and required improvement on the low level, control and pow-er systems

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA15

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Received ※ 14 August 2022 — Revised ※ 17 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 02 September 2022

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MOPOPA17

RF Commissioning of the First-of-Series Cavity Section of the Alvarez 2.0 at GSI

DTL, operation, vacuum, coupling

106

M. Heilmann, L. Groening, C. Herr, M. Hoerr, S. Mickat, B. Schlitt, G. Schreiber
GSI, Darmstadt, Germany

The existing post-stripper DTL of the GSI UNILAC will be replaced with the new Alvarez 2.0 DTL to serve as the injector chain for the Facility of Antiproton and Ion Research (FAIR). The 10⁸.4 MHz Alvarez 2.0 DTL with a total length of 55 meters has an input energy of 1.36 MeV/u and the output energy is 11.32 MeV/u. The presented First-of-Series (FoS) cavity section with 11 drift tubes and a total length of 1.9 m is the first part of the first cavity of the Alvarez 2.0 DTL. After copper plating and assembly of the cavity the RF-conditioning started in July 2021. These proceeding gives an overview on the results of the successfully RF-conditioning to reach the necessary gap voltage for uranium operation including a comfortable safety margin.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA17

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Received ※ 24 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022

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MOPOPA19

Preparation for Commissioning with Beam of "Advanced Demonstrator" Module with Heavy Ion Beam

linac, heavy-ion, MMI, solenoid

114

M. Miski-Oglu, W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, T. Kürzeder, S. Lauber, J. List, S. Yaramyshev
HIM, Mainz, Germany
W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, S. Yaramyshev
GSI, Darmstadt, Germany
W.A. Barth, F.D. Dziuba, S. Lauber, J. List
KPH, Mainz, Germany
H. Podlech, M. Schwarz
IAP, Frankfurt am Main, Germany

The integration of the accelerator components in to the cryogenic module prototype (Advanced Demonstrator) is a major milestone of the R&D for the superconducting heavy ion continuous wave linear accelerator HELIAC at GSI. The HELIAC is joint project of Helmholtz Institute Mainz (HIM) and GSI developed in collaboration with IAP Goethe University Frankfurt. This module is equipped with three superconducting (sc) Cross bar H-mode (CH) acceleration cavities CH0-CH2 and a sc rebuncher cavity, as well as two sc solenoids. The commissioning of the cryogenic module with Argon beam at GSI is scheduled for August 2023. In preparation for the beam test activities, the beamline, which connects the High Charge State Injector (HLI) with the testing area, has been installed. The beamline comprises a pair of phase probes for Time Of Flight (TOF) measurement of the incoming beam energy, quadrupole lenses and a 4-gap RF-buncher cavity. The beam diagnostics bench behind the cryo module is equipped with phase probe pairs, a slit-grid device, a bunch shape monitor (Feshenko monitor) for measurements of the longitudinal beam profile. The bench allows complete 6d characterization of the ion beam.

Poster MOPOPA19 [3.074 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA19

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Received ※ 24 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 04 September 2022

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MOPOPA20

Q Drop Tendency of Half-Wave Resonator Cavity

radiation, ECR, vacuum, superconducting-cavity

118

Y. Jung, H. Jang, H. Kim, H. Kim, J.W. Kim
IBS, Daejeon, Republic of Korea
S. Jeon
Kyungpook National University, Daegu, Republic of Korea

All HWRs (half-wave resonator superconducting cavities) have been fabricated and installed in the low energy section of the LINAC in IBS. All HWR cavities have been tested (vertical tests, VT) both at 4.2 K and 2.1 K cryogenic surroundings although operating temperature of HWRs is 2.1 K. Good cavities of high quality factors showed the Q drop tendency of 2.1 k were very similar to that of 4.2 K. However, in many cases, Q drop tendency of 2.1 K were not similar with 4.2 K, rather Q decreased more rapidly than 4.2 K which means the surface resistance of the cavity rapidly increased at 2 K surrounding. In this study, we will report that various Q results of HWRs and compare their Q drop tendency as a function of temperature, 2.1 K and 4.2 K.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA20

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Received ※ 23 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022

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MOPOGE01

Linac Design within HITRIplus for Particle Therapy

linac, synchrotron, rfq, operation

134

U. Ratzinger, H. Höltermann, B. Koubek, H. Podlech
BEVATECH, Frankfurt, Germany
M. Vretenar
CERN, Meyrin, Switzerland

Funding: EU Horizon 2020 Grant agreement No 101008548
Within the EU H2020 project HITRIplus for the development of cancer therapy with heavy ions a linac was designed. It is evolving from the concept of the 4 European cancer therapy centers applying light ions up to carbon. The new linac will in its simpliest version allow C⁴⁺ - beam injection into synchrotrons at 5 A MeV, with high beam transmission and allowing currents up to 5 mA alpha - particles. An advanced ECR - ion source will inject into an RFQ - IH-DTL combination. The DTL concept allows upgraded versions for A/q - values up to two and with beam energies of 7.1 A MeV from IH - tank2 and 10 A MeV from IH-tank3. The higher beam injection energies for light ions allow a relaxed synchrotron operation at lowest magnetic field levels. A main argument for the DTL extensions however is an additional linac function as radioisotope facility driver. The 7.1 A MeV are especially defined for the clean production of 211At, which may play a future role in cancer therapy. The linac will allow for high duty factors - up to 10%, to fulfil the needs for efficient radioisotope production. Solid state amplifiers with matched design RF power levels (up to 600 kW for IH3) will be used.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE01

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Received ※ 24 August 2022 — Revised ※ 27 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 07 September 2022

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MOPOGE04

Cell Geometry Optimization for Dipole Kick Correction in a High-Frequency IH Structure

dipole, linac, DTL, impedance

146

R. López López, P. Calvo, D. Gavela, J. Giner Navarro, G. Moreno, C. Oliver, J.M. Pérez Morales
CIEMAT, Madrid, Spain
M.C. Battaglia, J.M. Carmona
AVS, Elgoibar, Spain
A.M. Lombardi
CERN, Meyrin, Switzerland

Funding: CIEMAT
Given the asymmetry in the stem configuration of an IH-DTL structure, an electric dipole component is always present between drift tubes, and it is especially significant for reduced dimensions in high-frequency regimes. Here we study the effect of different modifications of the drift tubes geometry of a 750 MHz IH-DTL to eliminate the impact of the dipole component in the transverse beam dynamics. Tracking simulations through a single cell are also performed to assess the outcomes in particle’s trajectory offset and angle.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE04

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Received ※ 24 August 2022 — Revised ※ 27 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 04 September 2022

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MOPOGE05

Effect of High-Magnetic Field Region Geometry on the Efficiency of a 750 MHz IH Structure

linac, simulation, impedance, software

150

G. Moreno, P. Calvo, D. Gavela, J. Giner Navarro, R. López López, C. Oliver, J.M. Pérez Morales
CIEMAT, Madrid, Spain
M.C. Battaglia, J.M. Carmona
AVS, Elgoibar, Spain
A.M. Lombardi
CERN, Meyrin, Switzerland

Funding: CIEMAT
High frequency structures generally translate to high efficiency performances thanks to reduced surfaces of the inner cavity. Two round-profiles geometry and some variations of two important parameters of a 750 MHz IH-DTL are proposed in this paper in order to improve shunt impedance performance regarding an existing solution with flat-walled cavity developed by CERN. The proposed designs are shaped such that they guarantee an easy connection of RF and vacuum auxiliaries. Electromagnetic simulations are checked with CST Microwave Studio.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE05

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Received ※ 20 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 27 August 2022 — Issue date ※ 13 October 2022

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MOPOGE06

Automatic RF Conditioning of S-Band Cavities for Commercial Proton Therapy Linacs

vacuum, controls, linac, GUI

154

S. Benedetti, M. Cerv, S. Magnoni, J.L. Navarro Quirante, S.G. Soriano
AVO-ADAM, Meyrin, Switzerland

The CERN spinoff company ADAM owned by Advanced Oncotherapy plc (AVO-ADAM) is completing the construction and testing of its first LIGHT (Linac for Image-Guided Hadron Therapy) system. Each LIGHT machine is composed by 20 accelerating modules: one 750 MHz RFQ, four 3 GHz Side-Coupled Drift Tube Linac (SCDTL) and 15 3 GHz Coupled-Cavity Linac (CCL). The company aims at delivering several similar LIGHT machines in the next years. A prerequisite to achieve such goal is the capability to complete the RF conditioning of the accelerating modules in a systematic and automatic way, with minimal inputs from RF engineers. In the past years ADAM developed an automatic conditioning system capable of increasing the main conditioning parameters ’ RF power, pulse width, repetition rate ’ while controlling the cavity breakdown rate and vacuum level. The system has been so far tested on about twenty accelerating structures with different brazing methodologies and RF accelerating voltages, proving its robustness. This paper discusses the ADAM automatic conditioning system design and its implementation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE06

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Received ※ 13 August 2022 — Revised ※ 17 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 31 August 2022

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MOPOGE07

High Power RF Transmission Lines of the Light Proton Therapy Linac

network, linac, proton, controls

158

J.L. Navarro Quirante, D. Aguilera Murciano, S. Benedetti, G. Castorina, C. Cochrane, G. De Michele, J. Douthwaite, A. Eager, S. Fanella, M. Giles, D. Kaye, V.F. Khan, J. Mannion, J. Morris, J.F. Orrett, N. Pattalwar, E. Rose, D. Soriano Guillén
AVO-ADAM, Meyrin, Switzerland

The LIGHT (Linac for Image-Guided Hadron Therapy) machine is designed to accelerate a proton beam up to 230 MeV to treat deep seated tumours. The machine consists of three different kinds of accelerators: RFQ (Radio-Frequency Quadrupole), SCDTL (Side Coupled Drift Tube Linac) and CCL (Coupled Cavity Linac). These accelerating structures are fed with RF power at 750 MHz (RFQ) and 3 GHz (SCDTLs and CCLs). This power is delivered to the accelerating structure via the high power RF transmission network (RF network). In addition, the RF network needs to offer other functionalities, like protection of the high RF power feeding stations, power splitting, phase and amplitude control and monitoring. The maximum power handling of the RF network corresponds to a peak RF power of 8 MW and an average RF power of 9 kW. It functions either in Ultra-High Vacuum (UHV) conditions at an ultimate operating pressure of 10^-7 mbar, or under pressurized gas. The above listed requirements involve different challenges. In this contribution we exhibit the main aspects to be considered based on AVO experience during the commissioning of the RF network units.

Poster MOPOGE07 [1.075 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE07

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Received ※ 22 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 02 September 2022

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MOPOGE08

Low Level RF System of the Light Proton Therapy Linac

LLRF, linac, controls, rfq

161

D. Soriano Guillén, S. Benedetti, M. Cerv, G. De Michele, Ye. Ivanisenko
AVO-ADAM, Meyrin, Switzerland

The LIGHT (Linac for Image-Guided Hadron Therapy) project was initiated to develop a modular proton accelerator delivering beam with energies up to 230 MeV for cancer therapy. The machine consists of three different kinds of accelerating structures: RFQ (Radio-Frequency Quadrupole), SCDTL (Side Coupled Drift Tube Linac) and CCL (Coupled Cavity Linac). These accelerating structures operate at 750 MHz (RFQ) and 3 GHz (SCDTL, CCL). The accelerator RF signals are generated, distributed, and controlled by a Low-Level RF (LLRF) system. The LIGHT LLRF system is based on a commercially available solution from Instrumentation Technologies with project specific customization. This LLRF system features high amplitude and phase stability, monitoring of the RF signals from the RF network and the accelerating structures at 200 Hz, RF pulse shaping over real-time interface integrated, RF breakdown detection, and thermal resonance frequency correction feedback. The LLRF system control is integrated in a Front-End Controller (FEC) which connects it to the LIGHT control system. In this contribution we present the main features of the AVO LLRF system, its operation and performance.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE08

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Received ※ 16 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 05 September 2022

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MOPOGE10

A Medical Linac for Affordable Proton Therapy

proton, linac, cyclotron, radiation

167

S. Hunt, J. Adélise, W.D. Klotz, R. Seviour, E.D. van Garderen
Alceli Limited, Aberdeen, United Kingdom
D. Correia
PSI, Villigen PSI, Switzerland

Proton Therapy (PT) was first proposed in the 1940s. Application of this knowledge was largely led over the next fifty years by accelerator laboratories, but now also by commercial companies. Availability of PT is increasing but is limited by three factors: facility size, prompt/induced radiation, and treatment cost. Compact cyclotrons/synchro cyclotrons for single-room facilities have reduced space requirements. linacs can avoid high radiation levels. Yet treatment costs have remained stubbornly high, driven largely by maintenance and staffing costs over the typical 20-30 year facility lifetime. Current technology cannot simultaneously reduce these three factors. By using a long linac, the Alceli approach sacrifices size limitations, to gain massive improvements in treatment cost and radiation levels. Quadrupling the length of a linac results in a sixteen-fold reduction in RF power per cavity. Along with other innovations in our design, this leads to a modular warm linac with distributed solid-state RF amplification, easy and cheap to manufacture and maintain, requiring no water cooling, and a treatment cost of 1/10th of current facilities, making PT much more affordable.

Slides MOPOGE10 [1.934 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE10

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Received ※ 15 August 2022 — Revised ※ 23 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022

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MOPOGE11

Update on the First 3D Printed IH-Type Linac Structure - Proof-of-Concept for Additive Manufacturing of Linac RF Cavities

vacuum, linac, simulation, experiment

170

H. Hähnel, A. Ateş, U. Ratzinger
IAP, Frankfurt am Main, Germany

Funding: This research was funded by BBMBF grant number 05P21RFRB2.
Additive manufacturing ("AM" or "3D printing") has become a powerful tool for rapid prototyping and manufacturing of complex geometries. A 433 MHz IH-DTL cavity has been constructed to act as a proof of concept for additive manufacturing of linac components. In this case, the internal drift tube structure has been produced from 1.4404 stainless steel using AM. We present the concept of the cavity as well as first results of vacuum testing, materials testing and low level rf measurements. Vacuum levels sufficient for linac operation have been reached with the AM linac structure.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE11

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Received ※ 22 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 02 September 2022

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MOPOGE12

Cavity R&D for HBS Accelerator

simulation, neutron, brilliance, proton

174

N.F. Petry, K. Kümpel, S. Lamprecht, O. Meusel, H. Podlech, M. Schwarz
IAP, Frankfurt am Main, Germany

The demand for neutrons of various types for research is growing day by day worldwide. To meet the growing demand the Jülich High Brilliance Neutron Source (HBS) is in development. It is based on a high power linear proton accelerator with an end energy of 70 MeV and a proton beam current of 100 mA. The main part of the accelerator consists of about 45 CH-type cavities. As the current beam dynamic layout is still work in progress the number of cavities can change for the final design. For this beam dynamic layout the design of the CH-type cavities was optimized to handle the high accelerating gradient. The results of the performance of the CH-type cavities will be presented in this paper.

Poster MOPOGE12 [1.286 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE12

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Received ※ 17 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 15 September 2022

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MOPOGE13

Acceleration Efficiency of TE-Mode Structures for Proton Linacs

DTL, proton, simulation, impedance

177

J. Tamura, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
F. Naito, M. Otani
KEK, Tokai, Ibaraki, Japan

Various types of cavity structures are typically used in hadron linacs, depending on the energy range of the beam particle. This is especially the case in a normal-conducting linac, because the cavity’s acceleration efficiency varies with the velocity of the synchronous particle. For low-energy proton acceleration, while Alvarez drift-tube linacs (DTLs) are the most prevalent, TE-mode accelerating structures, which could also be called H-mode structures, are also widely used immediately after an initial radiofrequency quadrupole linac (RFQ). At present, the representative structures of TE modes are interdigital H-mode (IH) DTL and crossbar H-mode (CH) DTL, which are based on the TE11-mode pillbox cavity and TE21-mode pillbox cavity, respectively. In this presentation, acceleration efficiency of TE-mode structures including higher-order TE-modes such as TE31 and TE41 was comparatively reviewed with Alvarez DTL. This study shows that IH-DTL and CH-DTL have a larger shunt impedance than Alvarez DTL for proton acceleration below 10 MeV, and furthermore for the TEm1-mode structures, the rotational symmetry of the electric field improves with increasing angular index m.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE13

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Received ※ 30 August 2022 — Revised ※ 06 September 2022 — Accepted ※ 14 September 2022 — Issue date ※ 26 September 2022

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MOPOGE14

Current Status of the Spoke Cavity Prototyping for the JAEA-ADS Linac

linac, simulation, status, SRF

180

J. Tamura, Y. Kondo, F. Maekawa, S.I. Meigo, B. Yee-Rendón
JAEA/J-PARC, Tokai-mura, Japan
T. Dohmae, E. Kako, H. Sakai, K. Umemori
KEK, Ibaraki, Japan

The Japan Atomic Energy Agency (JAEA) has proposed an accelerator-driven subcritical system (ADS) to efficiently reduce high-level radioactive waste generated at nuclear power plants. One of the challenging R&D aspects of ADS is the reliability of the accelerator. In preparation for the full-scale design of the CW proton linac for the JAEA-ADS, we are now prototyping a low-beta (around 0.2) single spoke cavity. Since there is no experience in Japan in manufacturing a superconducting spoke cavity, prototyping and performance testing of the cavity is essential to ensure the feasibility of the JAEA-ADS linac. In the Japanese fiscal year 2021, we have started welding cavity parts together. By preliminarily examining the electron beam welding conditions, each press-formed niobium part was joined with a smooth welding bead. The current status of the spoke cavity prototyping for the JAEA-ADS linac is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE14

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Received ※ 01 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 14 September 2022 — Issue date ※ 26 September 2022

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MOPOGE16

Development of High-Gradient Accelerating Structures for Proton Radiography Booster at LANSCE

booster, linac, proton, coupling

188

S.S. Kurennoy, Y.K. Batygin, E.R. Olivas
LANL, Los Alamos, New Mexico, USA

Increasing energy of proton beam at LANSCE from 800 MeV to 3 GeV improves radiography resolution ~10 times. We propose accomplishing this energy boost with a compact cost-effective linac based on normal conducting high-gradient (HG) RF accelerating structures. Such an unusual proton linac is feasible for proton radiography (pRad), which operates with very short beam (and RF) pulses. For a compact pRad booster at LANSCE, we have developed a multi-stage design: a short L-band section to capture and compress the 800-MeV proton beam from the existing linac followed by the main HG linac based on S- and C-band cavities, and finally, by an L-band de-buncher*. Here we present details of development, including EM and thermal-stress analysis, of proton HG structures with distributed RF coupling for the pRad booster. A short test structure is designed specifically for measurements at the LANL C-band RF Test Stand.
* S.S. Kurennoy, Y.K. Batygin. IPAC21, MOPAB210.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE16

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Received ※ 23 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 03 September 2022

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MOPOGE17

CST Modeling of the LANSCE Coupled-Cavity Linac

alignment, linac, quadrupole, emittance

191

S.S. Kurennoy, Y.K. Batygin
LANL, Los Alamos, New Mexico, USA

The 800-MeV proton linac at LANSCE consists of a drift-tube linac, which brings the beam to 100 MeV, followed by 44 modules of a coupled-cavity linac (CCL). Each CCL module contains multiple tanks, and it is fed by a single 805-MHz klystron. CCL tanks are multi-cell blocks of identical re-entrant side-coupled cavities, which are followed by drifts with magnetic quadrupole doublets. Bridge couplers - special cavities displaced from the beam axis - electromagnetically couple CCL tanks over such drifts within a module. We have developed 3D CST models of CCL tanks. The models are used to calculate electromagnetic fields in the tanks. Beam dynamics is modelled in CST for bunch trains with realistic beam distributions using the calculated RF fields and quadrupole magnetic fields. Beam dynamics results are crosschecked with other multi-particle codes and applied to evaluate effects of CCL misalignments.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE17

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Received ※ 22 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 02 September 2022

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MOPOGE21

A Superconducting 217 MHz Single Spoke Cavity for the Helmholtz Linear Accelerator at GSI

simulation, linac, resonance, SRF

200

F.D. Dziuba, K. Aulenbacher, W.A. Barth, V. Gettmann, T. Kürzeder, J. List, M. Miski-Oglu
HIM, Mainz, Germany
K. Aulenbacher, W.A. Barth, F.D. Dziuba
KPH, Mainz, Germany
K. Aulenbacher, W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu, S. Yaramyshev
GSI, Darmstadt, Germany
T. Conrad, H. Podlech, M. Schwarz
IAP, Frankfurt am Main, Germany

Funding: Work supported by GSI, HIM, BMBF Contr. No. 05P18UMRB2
A new superconducting (SC) continuous wave (CW) linac, providing high efficient heavy ion acceleration above the coulomb barrier, is going to be built at GSI to fulfill the upcoming demands in the research field of super heavy element (SHE) synthesis. The so called HELIAC (HElmholtz LInear ACcelerator) delivers ion beams in the energy range of 3.5 MeV/u and 7.3 MeV/u with a mass to charge ratio (A/z) of up to 6. Superconducting multi-gap crossbar-H-mode (CH) cavities with a resonance frequency of 217 MHz are used for beam acceleration. In addition, SC single spoke buncher cavities should ensure longitudinal beam matching to the corresponding CH sections. Therefore, the first 217 MHz single spoke cavity with beta 0.07 has been developed at HIM/GSI and built at an industrial partner. In this paper the design of the cavity and first RF measurements during manufacturing are presented.

Poster MOPOGE21 [2.619 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE21

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Received ※ 18 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 27 August 2022 — Issue date ※ 31 August 2022

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MOPOGE23

Conservation of Quality Factor for Superconducting Cavity and Heartbeat under Relativistic Motion

acceleration, superconducting-cavity, resonance, ECR

204

H. Kim
IBS, Daejeon, Republic of Korea

Funding: This research was supported by the Rare Isotope Science Project of Institute for Basic Science funded by Ministry of Science and National Research Foundation of Korea (NRF-2013M7A1A1075764).
The conservation of quality factor under relativistic motion is applied to the superconducting cavity as well as the heartbeat of mammal. The quality factor of the superconducting cavity is conserved under relativistic motion. The frequency of the cavity decreases and the decay time increases as the velocity and acceleration are increased. The quality factor of the superconducting cavity is comparable with the total heartbeat of the mammal. The quality factor for the heartbeat of the mammal representing the total number of heartbeat is also conserved under relativistic motion. Therefore, the heart rate is inversely proportional to the life expectancy under relativistic motion.

Poster MOPOGE23 [0.765 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE23

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Received ※ 25 July 2022 — Revised ※ 23 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 02 September 2022

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MOPOGE24

Understanding Q Slope of Superconducting Cavity with Magnetic Defect and Field Emission

superconducting-cavity, radiation, ECR, cryomodule

208

H. Kim, Y. Jung, H. Kim, J.W. Kim
IBS, Daejeon, Republic of Korea
S. Jeon
Kyungpook National University, Daegu, Republic of Korea

Funding: This research was supported by the RISP of ibs funded by the Ministry of Science and the National Research Foundation (NRF) of the Republic of Korea under Contract 2013M7A1A1075764.
RF test for quarter-wave resonator (QWR) and half-wave resonator (HWR) superconducting cavities is performed at low temperature. The quality factors of the superconducting cavities are measured as a function of accelerating field. The magnetic heating effect for the quarter-wave resonator (QWR) is studied. For the half-wave resonator (HWR), the Q slope degradation is investigated with x-ray radiation and field emission.

Slides MOPOGE24 [2.506 MB]

Poster MOPOGE24 [1.174 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE24

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Received ※ 25 July 2022 — Revised ※ 18 August 2022 — Accepted ※ 23 August 2022 — Issue date ※ 12 October 2022

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MOPOGE25

Rf Measurement and Characterisation of European Spallation Source Cavities at UKRI-STFC Daresbury Laboratory and DESY

radiation, detector, cryomodule, MMI

212

P.A. Smith, A.E.T. Akintola, K.D. Dumbell, M.J. Ellis, S. Hitchen, P.C. Hornickel, C.R. Jenkins, A.J. May, P.A. McIntosh, K.J. Middleman, A.J. Moss, S.M. Pattalwar, M.D. Pendleton, J.O.W. Poynton, A.E. Wheelhouse, S. Wilde
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
G. Jones, M. Lowe, D.A. Mason, G. Miller, J. Mutch, A. Oates, J.T.G. Wilson
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
K.J. Middleman
Cockcroft Institute, Warrington, Cheshire, United Kingdom
D. Reschke, L. Steder, M. Wiencek
DESY, Hamburg, Germany

The Accelerator Science and Technology Centre (ASTeC) is responsible for delivering 88 High Beta (HB) cavities as part of the European Spallation Source (ESS) facility in Sweden. The bulk Niobium Superconducting Radio Frequency (SRF) cavities operate at 704 MHz. They have been fabricated in industry and are currently being tested at Daresbury Laboratory and Deutsches Elektronen-Synchrotron (DESY). They will then be delivered to Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA) Saclay, France for integration into cryomodules. To date 50 cavities have been conditioned and evaluated and 36 cavities have been delivered to CEA. This paper discusses the experiences and testing of the cavities performed to date at both sites

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE25

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Received ※ 24 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 04 September 2022

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MOPORI08

Beam Mapping Linearity Improvement in Multi-Dimensional Bunch Shape Monitor

electron, focusing, detector, operation

239

S.V. Kutsaev, R.B. Agustsson, A.C. Araujo Martinez, A. Moro, A.Yu. Smirnov, K.V. Taletski
RadiaBeam, Santa Monica, California, USA
A.V. Aleksandrov, A.A. Menshov
ORNL, Oak Ridge, Tennessee, USA

Funding: This work was supported by the U.S. Department of Energy , Office of Basic Energy Sciences, under contract DE-SC0020590.
RadiaBeam is developing a Bunch Shape Monitor (BSM) with improved performance that incorporates three major innovations. First, the collection efficiency is im-proved by adding a focusing field between the wire and the entrance slit. Second, a new design of an RF deflector improves beam linearity. Finally, the design is augmented with both a movable wire and a microwave deflecting cavity to add functionality and enable measuring the transverse profile as a wire scanner. In this paper, we pre-sent the design of the BSM and its sub-systems.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI08

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Received ※ 24 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 02 September 2022 — Issue date ※ 09 September 2022

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MOPORI12

Development of Commercial RFQ Toward CW Applications

rfq, MMI, operation, neutron

255

H. Yamauchi, M. Masuoka
Time Corporation, Hiroshima, Japan

TIME Co. developed a new 4-vane RFQ structure that can be used for a very high-duty factor operation. We eliminated the tuners to flatten the field distribution. The tuners increase RF contacts which may trigger unex-pected local heat spots and subsequent discharges. In addition, we hollowed out the entire vane to achieve large cooling water channels. A high-power test showed that the commissioning was completed within one day. We could input a nominal RF power without experienc-ing almost any discharge. The applied duty factor was 5 % at the 200 MHz resonant frequency, and the meas-ured frequency shift was not detected.
These activities have been carried out in collaboration with Tokyo Institute of Technology and RIKEN.

Slides MOPORI12 [1.877 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI12

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Received ※ 26 August 2022 — Revised ※ 04 September 2022 — Accepted ※ 27 September 2022 — Issue date ※ 29 September 2022

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MOPORI18

Overview of STFC Daresbury Laboratory Vacuum Operations for the Testing of ESS High Beta Cavities.

vacuum, SRF, operation, detector

268

S. Wilde, K.J. Middleman, M.D. Pendleton, J.O.W. Poynton
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
D.A. Mason, G. Miller, J. Mutch
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
K.J. Middleman
Cockcroft Institute, Warrington, Cheshire, United Kingdom

This paper describes the vacuum systems and operations that are used at the STFC Daresbury Laboratory SuRF lab during cold RF testing of ESS high beta RF accelerating cavities. Dedicated slow pump slow vent (SPSV) systems are used to perform vacuum acceptance testing of each cavity before, during and after cold RF testing. Details of the vacuum systems, support facilities, acceptance criteria and test results will be discussed in detail.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI18

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Received ※ 24 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 02 September 2022 — Issue date ※ 09 September 2022

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MOPORI20

Fabrication, Field Measurement, and Testing of a Compact RF Deflecting Cavity for ELBE

pick-up, resonance, simulation, vacuum

271

T.G. Hallilingaiah, P. Michel, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
A. Arnold, S. Köppen, P. Michel
HZDR, Dresden, Germany
U. van Rienen
University of Rostock, Rostock, Germany

A transverse deflecting cavity is being developed for the electron linac ELBE to separate the bunches into two or more beamlines so that multiple user experiments can be carried out simultaneously. A normal conducting double quarter-wave cavity has been designed to deliver a transverse kick of 300 kV when driven by an 800 W solid-state amplifier at 273 MHz. The main challenges in fabrication were machining the complex cavity parts with high precision, pre-tuning the cavity frequency, and the final vacuum brazing within the tolerances, which are described in this paper. The reason for a low intrinsic quality factor measured during the low power test was investigated, and suitable steps were taken to improve the quality factor. The cavity field profiles obtained from the bead-pull measurement matched the simulation results. Further, the cavity was driven up to 1 kW using a modified pick-up antenna, and eventually, vacuum conditioning of the cavity was accomplished. The cavity fulfils the design requirements and is ready for beam tests.

Poster MOPORI20 [4.325 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI20

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Received ※ 14 August 2022 — Revised ※ 15 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 07 September 2022

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MOPORI22

High-Power Test of an APF IH-DTL Prototype for the Muon Linac

linac, DTL, experiment, simulation

275

Y. Nakazawa, H. Iinuma
Ibaraki University, Ibaraki, Japan
E. Cicek, H. Ego, K. Futatsukawa, N. Kawamura, T. Mibe, S. Mizobata, N. Saito, M. Yoshida
KEK, Ibaraki, Japan
N. Hayashizaki
Research Laboratory for Nuclear Research, Tokyo Institute of Technology, Tokyo, Japan
Y. Iwata
NIRS, Chiba-shi, Japan
R. Kitamura, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
M. Otani
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Y. Sue, K. Sumi, M. Yotsuzuka
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
Y. Takeuchi
Kyushu University, Fukuoka, Japan
T. Yamazaki
KEK, Tokai Branch, Tokai, Naka, Ibaraki, Japan
H.Y. Yasuda
University of Tokyo, Tokyo, Japan

A muon linac is under development for a new muon g-2/EDM experiment at J-PARC. The muons are cooled to about room temperature and then re-accelerated to 212 MeV by four linear accelerators to produce a low-emittance muon beam. In the low-beta section, a short-range acceleration cavity with high efficiency needs to be developed to suppress the decay of muons. We propose a 324 MHz inter-digital H-mode drift-tube linac (IH-DTL) with high acceleration efficiency. The cavity can be downsized by introducing the alternating phase focusing (APF) method that provides transverse focusing only with an E-field. We have developed a prototype cavity that accelerates muons up to 1.3 MeV to demonstrate the principle. In this paper, the result of the high power test of the APF IH-DTL prototype is reported.

Poster MOPORI22 [10.978 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI22

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Received ※ 13 August 2022 — Revised ※ 16 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 01 September 2022

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MOPORI24

Monte Carlo Model of High-Voltage Conditioning and Operation

simulation, linac, HOM, vacuum

283

W.L. Millar, W. Wuensch
CERN, Meyrin, Switzerland
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

To synthesise the experimental results and theory pertaining to high-field phenomena, a model has been developed to simulate the conditioning and operation of high-field systems. By using a mesh-based method, the high-field conditioning of any arbitrary geometry and surface electric field distribution may be simulated for both RF and DC devices. Several phenomena observed in previous high-field tests such as the probabilistic behaviour of vacuum arcs and the inhomogeneous distribution of arc locations are described by this approach.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI24

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Received ※ 20 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 15 September 2022

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MOPORI26

Limits on Standing Wave Cavity Performance Due to Thermal Effects

simulation, linac, proton, DTL

287

S.J. Smith, G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

After an RF cavity has been designed, a thermal analysis is typically performed to assess the effects of RF heating on the operating frequency and field flatness. A multi-physics approach (coupled electromagnetic, thermal, and mechanical) is normally employed, sometimes combined with computational fluid dynamics (CFD) simulations to incorporate flowing water, which is used for cooling in normal conducting structures. Performing a CFD analysis can add significant time to the design process because of the long and complex simulations and instead, approximations of the heat transfer coefficients and inlet/outlet water temperature rises are made and used directly in the multi-physics analysis. In this work, we first explore the limits of these approximations, identifying when they apply and how accurate they are. We then investigate different pipe geometries and water flow rates to find the thermal limits from RF heating on cavity performance.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI26

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Received ※ 17 August 2022 — Revised ※ 20 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 15 September 2022

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TU1AA02

Compact, Turn-Key SRF Accelerators

cryomodule, SRF, operation, controls

290

N.A. Stilin, A.T. Holic, M. Liepe, T.I. O’Connell, J. Sears, V.D. Shemelin, J. Turco
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

The development of simpler, compact Superconducting RF (SRF) systems represents a new subject of research in accelerator science. These compact accelerators rely on advancements made to both Nb₃Sn SRF cavities and commercial cryocoolers, which together allow for the removal of liquid cryogenics from the system. This approach to SRF cavity operation, based on novel conduction cooling schemes, has the potential to drastically extend the range of application of SRF technology. By offering robust, non-expert, turn-key operation, such systems enable the use of SRF accelerators for industrial, medical, and small-scale science applications. This presentation will provide an overview of the significant progress being made at Cornell, Jefferson Lab, and Fermilab (FNAL), including stable cavity operation at 10 MV/m. It will also introduce the primary challenges of this new field and their potential solutions, along with an overview of the various applications which could benefit the most from this technology.

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Slides TU1AA02 [4.683 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TU1AA02

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Received ※ 29 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 14 October 2022

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TU1AA03

R&D Towards High Gradient CW SRF Cavities

SRF, niobium, cryomodule, vacuum

295

D. Bafia, P. Berrutti, B. Giaccone, A. Grassellino, D.V. Neuffer, S. Posen, A.S. Romanenko
Fermilab, Batavia, Illinois, USA

This talk will discuss Fermilab’s recent progress in the surface engineering of superconducting radio-frequency (SRF) cavities geared toward producing simultaneously high quality factors and high accelerating gradients in cryomodules. We investigate possible microscopic mechanisms that drive improved performance by carrying out sequential RF tests on cavities subjected to low temperature baking. We compare performance evolution to observations made with material science techniques and find correlations with material parameters. We also discuss other key advancements that enable high gradient operation in cryomodules.

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Slides TU1AA03 [2.007 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TU1AA03

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Received ※ 20 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 16 October 2022

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TU1AA04

SWELL and Other SRF Split Cavity Development

HOM, GUI, vacuum, SRF

300

F. Peauger
CERN, Meyrin, Switzerland

An innovative superconducting cavity topology has been recently proposed at CERN and at Lancaster University. It integrates longitudinal slots crossing perpendicularly the RF surface. The RF current lines run along the slots, inducing no perturbation of the accelerating mode. Thanks to this approach, the cavity can be built using halves or quadrants, which is well appropriate to precise manufacturing techniques. This configuration allows direct access to the RF surface, thus facilitating the surface preparation and thin film deposition process in the case of cavities based on Nb/Cu technology. The contact faces between the cavity parts are moved to the slots’ ends where the electromagnetic fields are extremely low, thus relaxing the constraints on the quality of the assembly joints. This paper covers the latest development of a 600 MHz slotted elliptical cavity called SWELL, which has been proposed as an alternative option for the FCC-ee RF system as well as a simplified SWELL version of a single cell 1.3 GHz elliptical cavity and a new 6 GHz split resonator made of two halves for superconducting thin film characterization.
Acknowledgement of U. Van Rienen from Rostock University for the use of their GPU based workstations for RF simulations.

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Slides TU1AA04 [4.217 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TU1AA04

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Received ※ 14 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 02 September 2022

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TU1AA06

Next-Generation Nb₃Sn Superconducting RF Cavities

SRF, accelerating-gradient, radio-frequency, superconducting-RF

305

N.M. Verboncoeur, G. Gaitan, M. Liepe, R.D. Porter, L. Shpani, N.A. Stilin, Z. Sun
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Nb₃Sn currently is the most promising alternative material for next-generation, higher-performance SRF cavities. Significant recent progress has been made in further increasing efficiency, maximum field, and demonstrating readiness for first applications in actual accelerators. This paper will present an overview of worldwide recent progress in making this material a viable option for further accelerators.

Slides TU1AA06 [6.559 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TU1AA06

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Received ※ 31 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 04 September 2022 — Issue date ※ 09 September 2022

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TU2AA02

SPIRAL2 Final Commissioning Results

MMI, linac, rfq, operation

314

A.K. Orduz, P.-E. Bernaudin, M. Di Giacomo, R. Ferdinand, B. Jacquot, O. Kamalou, J.-M. Lagniel, G. Normand, A. Savalle
GANIL, Caen, France
D.U. Uriot
CEA-DRF-IRFU, France

The commissioning of SPIRAL2 was carried out in different steps and slots from 2014 to end 2021. In a first phase, the proton-deuteron and heavy ion sources, LEBT lines and RFQ were commissioned and validated with A/Q=1 up to 3 particles. The validation of the MEBT (between the RFQ and the linac, including the Single Bunch Selector), linac and HEBT lines (up to the beam dump and to the NFS experimental room) started on July 2019, when GANIL received the authorization to operate SPIRAL2. The linac tuning is now validated with H⁺, 4He2+ and D⁺ and nominal H⁺ and D⁺ beams were sent to NFS for physics experiments. The main results obtained during the commissioning stages and the strategy used by the commissioning team are presented.

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Slides TU2AA02 [3.724 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TU2AA02

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Received ※ 24 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 02 September 2022

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TUPOJO03

Optimized Beam Optics Design of the MINERVA/MYRRHA Superconducting Proton Linac

linac, target, diagnostics, rfq

337

U. Dorda, L. De Keukeleere
SCK•CEN, Mol, Belgium
F. Bouly, E. Froidefond
LPSC, Grenoble Cedex, France
E. Bouquerel, E.K. Traykov
IPHC, Strasbourg Cedex 2, France
L. Perrot
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France

The MYRRHA design for an accelerator driven system (ADS) is based on a 600 MeV superconducting proton linac. The first stage towards its realization is called MINERVA and was approved in 2018 to be constructed by SCK•CEN in Belgium. This 100 MeV linac, will serve as technology demonstrator for the high MYRRHA reliability requirements as well as driver for two independent target stations, one for radio-isotope research and production of radio-isotopes for medical purposes, the other one for fusion materials research. This contribution gives an overview of the latest accelerator machine physics design with a focus on the optimized medium (17 MeV) and high energy (100 MeV) beam transfer lines.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO03

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Received ※ 16 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 02 September 2022

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TUPOJO04

R&D for the Realization of a Very High Frequency Crossbar H-Mode Drift Tube Linac

DTL, linac, vacuum, coupling

341

M. Heilmann, C. Zhang
GSI, Darmstadt, Germany
H. Podlech
IAP, Frankfurt am Main, Germany

A 704.4 MHz Crossbar H-mode (CH) drift tube linac has been proposed for performing a radio frequency jump at ß = 0.2. Up to now, the highest frequency of the constructed CH cavities is 360 MHz. Simulations have shown that the operation frequency for an H210-mode cavity can be up to ~800 MHz. At 704.4 MHz, the cavity dimensions become small, which bring challenges for many practical problems e.g. construction, vacuum pumping and RF coupling. This paper presents the performed R&D studies for the realization of such a very high frequency cavity.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO04

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Received ※ 14 August 2022 — Revised ※ 19 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 31 August 2022

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TUPOJO05

Welding and Copper Plating Investigations on the FAIR Proton Linac

proton, linac, simulation, coupling

345

A. Seibel, T. Dettinger, C.M. Kleffner, K. Knie, C. Will
GSI, Darmstadt, Germany
M.S. Breidt, H. Hähnel, U. Ratzinger
IAP, Frankfurt am Main, Germany
J. Egly
PINK GmbH Vakuumtechnik, Wertheim, Germany

A FAIR injector linac for the future FAIR facility is under construction. In order to meet the requirements for copper plating of the CH-cavities, a variety of tests with dummy cavities has been per-formed and compared to simulation. Further dummy cavities have been produced in order to improve the welding techniques. In addition, the results on 3d-printed stems with drift tubes will be presented.

Poster TUPOJO05 [2.863 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO05

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Received ※ 08 August 2022 — Revised ※ 14 August 2022 — Accepted ※ 24 August 2022 — Issue date ※ 15 September 2022

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TUPOJO09

High Power RF Conditioning of the ESS DTL1

DTL, vacuum, controls, operation

356

F. Grespan, C. Baltador, L. Bellan, D. Bortolato, M. Comunian, E. Fagotti, M.G. Giacchini, M. Montis, A. Palmieri, A. Pisent
INFN/LNL, Legnaro (PD), Italy
F. Grespan, B. Jones, L. Page, A.G. Sosa, E. Trachanas, R. Zeng
ESS, Lund, Sweden
D.J.P. Nicosia
CERN, Meyrin, Switzerland

The first tank of Drift Tube Linac (DTL) for the European Spallation Source ERIC (ESS), delivered by INFN, has been installed in the ESS tunnel in Summer 2021. The DTL-1 is designed to accelerate a 62.5 mA proton beam from 3.62 MeV up to 21 MeV. It consists of 61 accelerating gaps, alternate with 60 drift tubes equipped with Permanent Magnet Quadrupole (PMQ) in a FODO lattice. The remaining drift tubes are equipped with dipole correctors (steerers), beam position monitors (BPMs) or empty. The total length of the cavity is 7.6 m and it is stabilized by post couplers. Two waveguide couplers feed the DTL with the 2.2 MW of RF power required for beam operation, equally divided by RF power losses and beam power. This paper first presents the main systems required for the DTL conditioning. Then it summarizes the main steps and results of this high power RF conditioning done at ESS to prepare the DTL for the consequent beam commissioning.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO09

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Received ※ 15 August 2022 — Revised ※ 19 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 15 September 2022

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TUPOJO14

Status of Testing and Commissioning of the Medium Energy Beam Transport Line of the ESS Normal Conducting Linac

MEBT, linac, MMI, quadrupole

376

A.G. Sosa, R.A. Baron, H. Danared, C.S. Derrez, E.M. Donegani, M. Eshraqi, V. Grishin, A. Jansson, M. Jensen, B. Jones, E. Laface, B. Lagoguez, Y. Levinsen, J.P.S. Martins, N. Milas, R. Miyamoto, D.J.P. Nicosia, D. Noll, D.C. Plostinar, T.J. Shea, R. Tarkeshian, C.A. Thomas, E. Trachanas, P.L. van Velze
ESS, Lund, Sweden
I. Bustinduy, A. Conde, D. Fernández-Cañoto, N. Garmendia, P.J. González, G. Harper, A. Kaftoosian, J. Martin, I. Mazkiaran, J.L. Muñoz, A.R. Páramo, S. Varnasseri, A.Z. Zugazaga
ESS Bilbao, Zamudio, Spain

The latest beam commissioning phase of the Normal Conducting Linac at ESS delivered a proton beam through the Medium Energy Beam Transport (MEBT) into the first Drift Tube Linac (DTL) tank. The probe beam in MEBT consisted of 3.6 MeV protons of <6 mA, <5 microseconds pulse length and 1 Hz repetition rate. Following the delivery of the components at ESS in Lund in June 2019, the commissioning phase with the MEBT was completed in July 2022. In March 2022, the maximum beam current of 62.5 mA was transported up to the MEBT Faraday cup. This proceeding focuses on the status of MEBT including magnets, buncher cavities, scrapers and beam diagnostics designed and tested in collaboration with ESS Bilbao.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO14

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Received ※ 13 August 2022 — Revised ※ 19 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 01 September 2022

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TUPOJO15

Commissioning of UKRI-STFC SRF Vertical Test and HPR Reprocessing Facility

SRF, MMI, cryogenics, vacuum

380

M.D. Pendleton, A.E.T. Akintola, R.K. Buckley, G. Collier, K.D. Dumbell, M.J. Ellis, S. Hitchen, P.C. Hornickel, G. Hughes, C.R. Jenkins, A.J. May, P.A. McIntosh, K.J. Middleman, A.J. Moss, S.M. Pattalwar, J.O.W. Poynton, P.A. Smith, A.E. Wheelhouse, S. Wilde
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
G. Jones, M. Lowe, D.A. Mason, G. Miller, C. Mills, J. Mutch, A. Oates, J.T.G. Wilson
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

Mark Pendleton, et al. The UK’s first and only vertical test facility and associated cleanroom reprocessing suite has been developed, commissioned, and entered steady-state operations at the UKRI-STFC Daresbury Laboratory. The facility is capable of 2 K testing of 3 jacketed SRF cavities in a horizontal configuration per 2-week test cycle. We report on the associated cryogenic, RF, UHV, mechanical, cleanroom, and HPR infrastructure. SRF cavity workflows have been developed to meet the requirements of the ESS high beta cavity project within a newly developed quality management system, SuraBee, in accordance with ISO9001. To support standardisation of measurements across the collaboration, reference cavities have been measured for cross-reference between CEA, DESY, and UKRI-STFC. We further report on commissioning objectives, observations, and continuous improvement activities.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO15

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Received ※ 24 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 05 September 2022 — Issue date ※ 08 September 2022

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TUPOJO17

High Efficiency High Power Resonant Cavity Amplifier For PIP-II

coupling, impedance, network, electron

384

R.E. Simpson, N. Butler, D.B. Cope, M.P.J. Gaudreau, M.K. Kempkes
Diversified Technologies, Inc., Bedford, Massachusetts, USA

An advanced high-power, high power density, solid state power amplifier (SSPA) was developed to replace Vacuum Electron Devices (VEDs). Diversified Technologies, Inc. (DTI) developed and integrated a resonant-cavity combiner with solid state amplifiers for the Proton Improvement Plan-II (PIP-II) at Fermilab. The architecture combines the power of N-many RF power transistors into a single resonant cavity that are surface-mounted and -cooled. The system is designed so that failure of individual transistors has negligible performance impact. Due to the electrical and mechanical simplicity, maintenance and logistics are simplified. DTI demonstrated the basic feasibility of a 50-100 kW class amplifier resonant cavity combiner system at 650 MHz. A single-cavity system reached 15 kW at 66% power-added efficiency with ten of 12 slots filled on only 1 of 2 cavities faces. The system further demonstrated the expected graceful degradation; an intermittent fault occurred on 1 of the 10 modules and the only observable effect was a reduction in output power to 13.3 kW with a slight reduction in efficiency. Combining of multiple cavities was also demonstrated at low power.

Poster TUPOJO17 [0.790 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO17

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Received ※ 16 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 15 September 2022

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TUPOJO18

Cavity Qualification and Production Update for SNS-PPU Cryomodules at Jefferson Lab

cryomodule, proton, SRF, neutron

387

P. Dhakal, E. Daly, J.F. Fischer, N.A. Huque
JLab, Newport News, Virginia, USA
M.P. Howell
ORNL, Oak Ridge, Tennessee, USA
J.D. Mammosser
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: This manuscript has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The Proton Power Upgrade (PPU) project at Oak Ridge National Lab’s Spallation Neutron Source (SNS) currently being constructed will double the proton beam power capability from 1.4 to 2.8 MW by adding seven cryomodules, each containing four six-cell high-beta (β = 0.81) superconducting radio frequency cavities. Research Instruments, located in Germany, built and processed the cavities at the vendor site, including electropolishing as the final active chemistry step. Twenty-eight cavities for seven cryomodules and an additional four cavities for a spare cryomodules were delivered to Jefferson Lab and first qualification tests were completed on all cavities as received from the vendor. The performance largely exceeded the requirements on quality factor and accelerating gradient. Here we present the status of initial cavity qualification tests, rework on unqualified cavities and final cavity qualification with helium vessel prior to installation in cryomodules. In addition, an update on cryomodule production is presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO18

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Received ※ 23 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 09 September 2022

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TUPOJO22

Progress of PIP-II Activities at IJCLab

HOM, SRF, experiment, niobium

402

P. Duchesne, N. Gandolfo, D. Le Dréan, D. Longuevergne, R. Martret, T. Pépin-Donat, F. Rabehasy, S. Roset, L.M. Vogt
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
P. Berrutti, M. Parise, D. Passarelli
Fermilab, Batavia, Illinois, USA

Since 2018, IJCLab is involved in PIP-II project on the design and development of accelerator components for the SSR2 (Single Spoke Resonator type 2) section of the superconducting linac. First pre-production components have been fabricated, surface processing and cavity qualification in vertical cryostat are on-going. IJCLab has upgraded its facilities by developing a new set-up to perform rotational BCP. The progress of all processing and testing activities for PIP-II project will be reported and, in particular, a dedicated study to qualify removal uniformity compared to static BCP will be presented.

Poster TUPOJO22 [1.997 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO22

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Received ※ 23 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 01 September 2022

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TUPOJO23

Accelerated Lifetime Test of Spoke Cavity Cold Tuning Systems for Myrrha

cryomodule, operation, SRF, vacuum

406

N. Gandolfo, S. Blivet, F. Chatelet, V. Delpech, D. Le Dréan, G. Mavilla, M. Pierens, H. Saugnac
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France

Within the framework of MINERVA, the first Phase of MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) project, IN2P3 labs are in charge of the developments of several accelerator elements. Among those, a fully equipped Spoke cryomodule prototype was constructed, it integrates two superconducting single spoke cavities operating at 2K, the RF power couplers and the associated cold tuning systems. The extreme reliability specified for this project motivated to conduct ALT (Accelerated Lifetime Test) on two extra cold tuning systems in cryomodule like environment. Thus, by gathering information from experimental data, many aspects can be enhanced like maintenance plan consolidation, determination of aging indicators and design optimization of the whole system and its sub components. This paper describes the complete ALT process from the studying elements and the test environment design, to the experimental results and findings.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO23

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Received ※ 15 August 2022 — Revised ※ 17 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 02 September 2022

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TUPOPA05

RFQ Performance During RF Conditioning and Beam Commissioning at ESS

rfq, beam-loading, multipactoring, MMI

418

R. Zeng, G.S. Fedel, B. Jones, R. Miyamoto, D.J.P. Nicosia, D. Noll, A.G. Sosa, A.M. Svensson, E. Trachanas
ESS, Lund, Sweden
M. Baudrier
CEA-DRF-IRFU, France
A.C. Chauveau, M.J. Desmons, P. Hamel, O. Piquet
CEA-IRFU, Gif-sur-Yvette, France
F. Grespan
INFN/LNL, Legnaro (PD), Italy

RFQ at ESS has been successfully gone through RF conditioning, RF re-conditioning and low duty cycle beam commissioning. RFQ fulfills required functions and overall performance is satisfactory. RF conditioning, three RF re-conditionings after LEBT intervention and beam commissioning will be reported and RFQ performance during these periods will be described. RFQ performance in a large extent is reflected by dynamics and interactions between RF, cavity and beam. Thanks to advanced hardware capabilities and intelligent software intelligence, observation of those dynamics and interactions are done in detailed level. Analysis of those dynamics and interaction will be introduced. Some techniques to deal with challenges resulted from those dynamics and interactions will also be discussed.

Poster TUPOPA05 [25.281 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA05

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Received ※ 18 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 05 September 2022

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TUPOPA11

Compact Proton Accelerator in UHF Band At KAHVELab

rfq, proton, vacuum, quadrupole

434

S. Esen, A. Adiguzel, O. Kocer, S. Oz
Istanbul University, Istanbul, Turkey
A. Caglar
YTU, Istanbul, Turkey
E. Celebi, E.V. Ozcan
Bogazici University, Bebek / Istanbul, Turkey
E. Celebi
IBU, Istanbul, Turkey
A.K. Karatay, F. Yaman, Ö.H. Yilmaz
IZTECH, Izmir, Turkey
U. Kaya
Istinye University, Institute of Sciences, Istanbul, Turkey
A. Kilicgedik
Marmara University, Istanbul, Turkey
G. Türemen
Turkish Atomic Energy Authority, Ankara, Turkey
G. Unel
UCI, Irvine, California, USA

Funding: This project are supported by TUBITAK Project no: 118E838
Proton Test Beam at KahveLAB (Kandilli Detector, Accelerator and Instrumentation Laboratory) project aims to design and produce a radio frequency quadrupole (RFQ) operating at 800 MHz in Istanbul, Turkey using the local resources. The beamline consists of a proton source, a low energy beam transport (LEBT) line including the beam diagnostic section, and the RFQ cavity itself. This RFQ is a 4-vane, 1-meter-long cavity to accelerate the 20 keV beam extracted from the plasma ion source to 2 MeV. Its engineering prototype is already produced and subjected to mechanical, low-power RF, and vacuum tests. In this poster, the results of the first test production, especially the bead-pull test setup will be discussed.

Poster TUPOPA11 [16.128 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA11

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Received ※ 21 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 12 September 2022 — Issue date ※ 26 September 2022

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TUPOPA15

Multipactor Studies: Simulations and Measurements on the RF Coaxial Resonator Test Bench

multipactoring, electron, simulation, experiment

445

Y. Gómez Martínez, J. Angot, M.A. Baylac, T. Cabanel, M. Meyer
LPSC, Grenoble Cedex, France
D. Longuevergne, G. Sattonnay
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France

Multipactor is an undesired phenomenon triggered by electromagnetic fields in accelerator components and more specifically in RF structures, such as accelerating cavities and power couplers, and may lead to Electron Cloud build up in beam tubes. The accelerator group at LPSC has developed an experimental setup dedicated to multipactor studies. It consists in a coaxial resonator, tunable and operational between 100 MHz and 1 GHz. It allows to characterize under real conditions the efficiency of surface treatment mitigation processes (coatings, cleaning procedures) at room temperature. This paper presents the experimental measurements performed with this setup confronted to simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA15

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Received ※ 12 August 2022 — Revised ※ 30 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 16 September 2022

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TUPOPA16

Complete Study of the Multipactor Phenomenon for the MYRRHA 80 kW CW RF Couplers

multipactoring, electron, simulation, linac

448

Y. Gómez Martínez, P.-O. Dumont, M. Meyer
LPSC, Grenoble Cedex, France
P. Duchesne, C. Joly, W. Kaabi
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France

MYRRHA [1] (Multi Purpose Hybrid Reactor for High Tech Applications) is an Accelerator Driven System (ADS) project. Its superconducting linac will provide a 600 MeV - 4 mA proton beam. The first project phase based on a 100 MeV linac is launched. The Radio-Frequency (RF) couplers have been designed to handle 80 kW CW (Continuous Wave) at 352.2 MHz. This paper describes the multipacting studies on couplers.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA16

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Received ※ 12 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 05 September 2022

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TUPOPA18

Test and Commissioning of the HELIAC Power Coupler

operation, cryomodule, multipactoring, heavy-ion

454

J. List, K. Aulenbacher, W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, M. Miski-Oglu, S. Yaramyshev
HIM, Mainz, Germany
K. Aulenbacher, W.A. Barth, F.D. Dziuba, S. Lauber, J. List
KPH, Mainz, Germany
K. Aulenbacher, W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu, S. Yaramyshev
GSI, Darmstadt, Germany
T. Conrad, H. Podlech, M. Schwarz
IAP, Frankfurt am Main, Germany

The superconducting continuous wave (cw) heavy ion HElmholtz LInear ACcelerator (HELIAC) is intended to be built at GSI in Darmstadt. With its high average beam current and repetition rate, the HELIAC is designed to fulfill the requirements of the super heavy element (SHE) research user program and the material sciences community at GSI. The accelerating cavities are of the superconducting Crossbar H-mode (CH) type, developed by GUF. Within the Advanced Demonstrator project, the first cryomodule, consisting of four cavities is scheduled for commissioning with beam in 2023. The former RF power couplers introduced a high heat input into the cryostat. Therefore, the coupler is redesigned at HIM in order to not only reduce the heat input but to provide an overall improved power coupler for the HELIAC. It is designed for maximal power of 5 kW cw at the frequency of 216.816 MHz. A prototype has been tested and commissioned recently. This includes several RF-tests at room temperature and in cryogenic environments. The results of these tests will be presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA18

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Received ※ 20 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 01 September 2022

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TUPOPA24

Design of an X-Band Bunching and Accelerating System for AWAKE Run 2

acceleration, electron, bunching, gun

458

J.M. Arnesano, S. Döbert
CERN, Meyrin, Switzerland

The AWAKE experiment at CERN demonstrated in its Run 1 that it is possible to accelerate electrons in plasma wakefields driven by a self-modulated proton bunch. In Run2, AWAKE aims to increase the accelerating gradient in the plasma even further and demonstrate beam quality in order to be ready for high-energy physics experiments. In this framework, a new electron injector, consisting of an S-band RF-gun and a subsequent X-band bunching and accelerating section, capable of producing very short bunches with a small emittance, has been designed. In this paper, two different configurations of the X-band section and their corresponding high-power distribution systems are presented. The first one consists of three identical cavities to bunch and accelerate the beam while the second one uses a separate short structure for velocity bunching followed by three long, pure accelerating structures. A discussion of the strengths and weaknesses of each configuration is carried out and beam dynamics aspects are analyzed. Finally the X-Band power distribution systems are described with particular attention to the choice of the klystron, the pulse compression system and the waveguide distribution.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA24

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Received ※ 12 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 16 September 2022

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TUPOPA25

Design, Manufacturing, Assembly, Testing, and Lessons Learned of the Prototype 650 MHz Couplers

vacuum, SRF, cryomodule, multipactoring

462

J. Helsper, S.K. Chandrasekaran, F. Furuta, B.M. Hanna, S. Kazakov, J.P. Ozelis, K.S. Premo, N. Solyak, G. Wu
Fermilab, Batavia, Illinois, USA

Funding: Work supported, in part, by the U.S. Department of Energy, Office of Science, Office of High Energy Physics, under U.S. DOE Contract No. DE-AC02-07CH11359.
Six 650 MHz high-power couplers will be integrated into the prototype High Beta 650 MHz (HB650) cryomodule for the PIP-II project at Fermilab. The design of the coupler is described, including design optimizations from the previous generation. This paper then describes the coupler life-cycle, including manufacturing, assembly, testing, conditioning and the lessons learned at each stage.

Poster TUPOPA25 [2.695 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA25

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Received ※ 24 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 02 September 2022

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TUPOPA27

Conceptual Analysis of a Compact High Efficiency Klystron

klystron, bunching, wiggler, focusing

466

J.P. Edelen, S.D. Webb
RadiaSoft LLC, Boulder, Colorado, USA
K.E. Nichols
LANL, Los Alamos, New Mexico, USA

Traditional klystron efficiencies are limited by the output electron beam harmonic current and energy spread. Increasing the amount of harmonic current produced in the klystron requires increasing the velocity bunching in the input cavity. Additional cavities may be used to improve the bunching, however they do so at additional cost and space requirements for the klystron. Moreover, at higher currents space charge counteracts this velocity bunching reducing the amount of harmonic current that can be produced. Our concept resolves these challenges by employing a new type of high-efficiency, multi-beam klystron. Our design consists of a single two-frequency input cavity, a wiggler, and an output cavity. The two-frequency input cavity approximates a linear function in time thereby increasing the harmonic content of the beam, while the wiggler provides strong longitudinal focusing to mitigate the effects of space charge. In this paper we provide the theoretical foundation for our design and present initial numerical calculations showing improved bunching from the harmonic mode and the wiggler.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA27

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Received ※ 14 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 31 August 2022

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TUPOPA30

Innovative Magnetron Power Sources for SRF Linacs

cathode, electron, simulation, power-supply

473

M. Popovic, M.A. Cummings, A. Dudas, R.P. Johnson, R.R. Lentz, M.L. Neubauer, T. Wynn
Muons, Inc, Illinois, USA
T. Blassick, J.K. Wessel
Richardson Electronics Ltd, Lafox, Illinois, USA
K. Jordan, R.A. Rimmer, H. Wang
JLab, Newport News, Virginia, USA

Funding: Supported in part by US Department of Energy Nuclear Physics SBIR Grant DE-SC0022484
Magnetron RF power sources for single cavities can cost much less and operate at much higher efficiency than klystrons, but they do not have the phase and amplitude control, or the lifetime, needed to drive SRF cavities for superconducting particle accelerators. Existing magnetrons that are typically used to study methods of control or lifetime improvements for SRF accelerators are built for much different applications such as kitchen microwave ovens (1kW, 2.45 GHz) or industrial heating (100 kW, 915 MHz). Muons, Inc. is working with Richardson Electronics LLC to develop fast and flexible manufacturing techniques to allow many ideas to be tested for construction variations that enable new phase and amplitude injection locking control methods, longer lifetime, and inexpensive refurbishing resulting in the lowest possible life-cycle costs. A magnetron suitable for 1497 MHz klystron replacements at Jefferson Lab has been designed, constructed, and tested.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA30

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Received ※ 16 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022

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TUPOGE01

Commissioning of the VECC Cryomodule

solenoid, MMI, ISAC, vacuum

476

Z.Y. Yao, R. Bjarnason, J. Cheung, K. Fong, J.J. Keir, D. Kishi, S. Kiy, P. Kolb, D. Lang, R.E. Laxdal, B. Matheson, R.S. Sekhon, B.S. Waraich, Q. Zheng, V. Zvyagintsev
TRIUMF, Vancouver, Canada

A quarter-wave resonator (QWR) cryomodule was designed and assembled at TRIUMF for the energy upgrade of the VECC ISOL-RIB facility to boost radioactive isotopes from 1MeV/u to 2MeV/u. The top loading cryomodule was chosen based on the ISAC-II low energy section design, consisting of four superconducting QWRs and one superconducting solenoid. The major change from ISAC-II concept is separating the RF space vacuum from the isolation vacuum. The cryogenic commissioning was recently completed. The cold mass alignments and the cryogenic heat loads were measured. The cavity performance was qualified in both test regime and operating regime. The cavity degradations caused by magnetic pollution from solenoid and the recovery procedure were verified. This paper will report the detailed results of the commissioning.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE01

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Received ※ 23 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 03 September 2022

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TUPOGE02

Three Years of Operation of the SPIRAL2 LINAC: Cryogenics and Superconducting RF Feedback

cryogenics, cryomodule, operation, linac

479

P.-E. Bernaudin, M. Aburas, M. Di Giacomo, A. Ghribi, P. Robillard, L. Valentin
GANIL, Caen, France

The superconducting LINAC of SPIRAL2 at the GANIL facility is in operation since October 2019. Its 26 super-conducting quarter wave resonating cavities (88 MHz) are operated at a nominal gradient of 6.5 MV/m, but most of the cavities can be operated up to 8 MV/m. They are integrated into 19 cryomodules and cooled down at 4 K by a dedicated refrigeration cryogenic system. In this paper, we will present a feedback after five years of operation of the cryogenic system, focusing on the main problems that have been faced, and on the diverse evolutions performed in order to improve the cryogenic system and to increase its reliability. We will also provide a feedback of the superconducting cavities performances status after three years of operation

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE02

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Received ※ 27 July 2022 — Revised ※ 22 August 2022 — Accepted ※ 26 August 2022 — Issue date ※ 15 September 2022

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TUPOGE03

Advanced Cryogenic Process Control and Monitoring for the SPIRAL2 Superconducting LINAC

controls, cryogenics, linac, cryomodule

483

A. Ghribi, M. Aburas, P.-E. Bernaudin, M. Di Giacomo, A.H. Trudel, Q. Tura
GANIL, Caen, France
P. Bonnay, F. Bonne
CEA/INAC, Grenoble Cedex 9, France
F. Millet
CEA, Grenoble, France

SPIRAL2 is a superconducting accelerator for protons, deuterons and heavy ions delivering a maximum beam power of 200 kW at 40 MeV (for deuteron beams). 26 superconducting quarter wave cavities are operated at 4.4 K, plunged in a liquid helium bath with a drastic phase separator pressure control. Previous years have seen the development of advanced process control for cryogenics allowing to cope with high heat load dynamics thanks to an automatic heat dissipation compensation and a model based control. The latter is based on models, using the Simcryogenics library, optimized and linearised in the Programmable Logic Controllers. The SPIRAL2 operation has demonstrated that such control allows to keep the specified conditions for RF and beam operation even at levels of heat load dissipation approaching the physical limits of the cryogenic system. These developments allowed to synthesise a virtual observer of the dynamic heat load dissipated by the cavities. The present paper summarises the development of such observer based on the physical thermodynamic model and on machine learning techniques.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE03

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Received ※ 24 August 2022 — Revised ※ 02 September 2022 — Accepted ※ 04 September 2022 — Issue date ※ 09 September 2022

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TUPOGE04

An Approach for Component-Level Analysis of Cryogenic Process in Superconducting LINAC Cryomodules

cryomodule, cryogenics, linac, multipactoring

487

C. Lhomme
IJCLab, ORSAY, France
D. Berkowitz Zamora, M.D. Grosso Xavier
SCK•CEN, Mol, Belgium
F. Chatelet, P. Duthil, H. Saugnac
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
F. Dieudegard, C. Lhomme
ACS, Orsay, France
T. Junquera
Accelerators and Cryogenic Systems, Orsay, France

Powerful superconducting linear accelerators feature accelerating sections consisting in a series of cryomod-ules (CM), each hosting superconducting radiofrequency (SRF) cavities cooled by a cryogenic process. Despite the extensive instrumentation used for the tests and valida-tion of the prototype cryomodules, it is usually very complex to link the measured global thermodynamic efficiency to the individual component performance. Previous works showed methods for assessing the global efficiency and even for allocating performances to sets of components, but few went down to a component level. For that purpose, we developed a set of techniques based on customized instrumentation, on dedicated test proto-cols, and on model-based analysis tools. In practice, we exposed the components to various operating conditions and we compared the measured data to the results from a detailed dynamic component model at the same condi-tions. This method was applied to the cryogenic debug-ging phase of the tests of the MINERVA prototype cry-omodule, which, despite the liquid helium shortage, led to an extensively detailed characterisation, for its valida-tion towards the serial construction.

Poster TUPOGE04 [1.234 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE04

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Received ※ 20 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022

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TUPOGE06

Performance Test of Mass-Production of HWR Cryomodules for SCL32

cryomodule, multipactoring, vacuum, linac

491

Y. Kim, J.W. Choi, D.H. Gil, H. Jang, Y.W. Jo, J. Joo, H.C. Jung, H. Kim, M.S. Kim, M. Kwon, M. Lee, J.H. Shin
IBS, Daejeon, Republic of Korea
Y.U. Sohn
PAL, Pohang, Republic of Korea

Funding: This work was supported by the Rare Isotope Science Project of Institute for Basic Science funded by Ministry of Science and ICT and NRF of Korea (2013M7A1A1075764)
Mass production of the HWR (half wave resonator) cryomodules for SCL32 of RAON had been conducted since 2018 and all cryomodules were installed in the SCL3 tunnel in 2021. Total number of the HWR cavities and the HWR cryomodules are 10⁶ and 34, respectively. Cryomodule performance test was started in September 2020 and finished in October 2021, except for one bunching cryomodule that will be installed in front of the high energy linac. The detailed procedure and the results of performance test is reported in detail.

Poster TUPOGE06 [1.211 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE06

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Received ※ 14 August 2022 — Revised ※ 23 August 2022 — Accepted ※ 12 September 2022 — Issue date ※ 15 September 2022

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TUPOGE07

Magnetic Field Measurements and Shielding at the UKRI-STFC Daresbury Laboratory SRF Vertical Test Facility

shielding, simulation, MMI, SRF

495

A.E.T. Akintola, A.R. Bainbridge, S. Hitchen, A.J. May, S.M. Pattalwar, P.A. Smith
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
M. Lowe, D.A. Mason, A.D. Shabalina
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

A novel vertical test facility has been developed, commissioned, and entered steady-state operations at the UKRI-STFC Daresbury Laboratory. The cryostat is designed to test 3 jacketed superconducting RF cavities in a horizontal configuration in a single cool-down run at 2 K. A 2-year program is currently underway to test ESS high-beta cavities. Upon completion of this program, the facility will undertake a testing program for PIP-II HB650 cavities. In the current configuration, a solution combining passive and active magnetic shielding has been validated for the ESS requirement of field attenuation to the level of <1 uT, although continuous field measurements are not provided. This paper reports the implementation of passive and active shielding, along with simulation and experimental measurements thereof.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE07

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Received ※ 22 August 2022 — Revised ※ 27 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 01 September 2022

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TUPOGE09

Steady-State Cryogenic Operations for the UKRI-STFC Daresbury SRF Vertical Test Facility

cryogenics, operation, MMI, SRF

501

A.J. May, A.E.T. Akintola, R.K. Buckley, G. Collier, K.D. Dumbell, S. Hitchen, P.C. Hornickel, G. Hughes, C.R. Jenkins, S.M. Pattalwar, M.D. Pendleton, P.A. Smith
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

A novel vertical test facility has been developed, commissioned, and entered steady-state operations at the UKRI-STFC Daresbury Laboratory. The cryostat is designed to test 3 jacketed superconducting RF cavities in a horizontal configuration in a single cool-down run at 2 K. The cavities are cooled with superfluid helium filled into their individual helium jackets. This reduces the liquid helium consumption by more than 70% in comparison with the conventional facilities operational elsewhere. The facility is currently undertaking a 2-year program to qualify 84 high-beta SRF cavities for the ESS (European Spallation Source) as part of the UK’s in-kind contribution. This paper reports on the steady-state operations, along with a detailed discussion of the cryogenic performance of the facility, including that of the cryoplant.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE09

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Received ※ 13 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 04 September 2022

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TUPOGE10

A Final Acceptance Test Kit for Superconducting RF Cryomodules

cryomodule, vacuum, cryogenics, SRF

504

A.J. May, A.E.T. Akintola, S.M. Pattalwar, A. White
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

UKRI-STFC Daresbury Laboratory is currently undertaking several projects involving assembly of superconducting RF cryomodules, including HL-LHC crab cavities and PIP-II HB650 cavities. As part of the final acceptance tests before shipping of the modules, extensive leak testing, pressure testing, and thermal cycling with gaseous and liquid must be performed. A Final Acceptance Test kit (FAT-kit) has been developed to support these tests. The FAT-kit, designed as a single portable unit, sits as an interface module between the cryomodule under test and the required utilities (liquid cryogen supply and return, gaseous cryogen supply and return, warm gas supply and return, vacuum pumps, leak detectors, etc.). The kit features a valve manifold to make or break connections to, from, and between circuits in the cryomodule, safety groupings to provide protection for the circuits as required, and various instrumentation. We report here on the design and commissioning of the kit.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE10

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Received ※ 23 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 15 September 2022

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TUPOGE11

Application of the ASME Boiler and Pressure Vessel Code in the design of SSR Cryomodule Beamlines for PIP-II Project at Fermilab

solenoid, alignment, cryomodule, operation

507

J. Bernardini, M. Chen, M. Parise, D. Passarelli
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Fermi Research Alliance, LLC under Contract No. DEAC02- 07CH11359 with the United States Department of Energy, Office of Science, Office of High Energy Physics.
This contribution reports the design of the main components used to interconnect SRF cavities and superconducting focusing lenses in the SSR Cryomodule beamlines, developed in the framework of the PIP-II project at Fermilab. The focus of the present contribution is on the design and testing of the edge-welded bellows according to ASME Boiler and Pressure Vessel Code. The activities performed to qualify the bellows to be assembled in cleanroom, for operation in high vacuum, cryogenic environments, and their characterization from magnetic standpoint, will also be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE11

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Received ※ 22 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 16 October 2022

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TUPOGE12

Final Design of the Pre-Production SSR2 Cryomodule for PIP-II Project at Fermilab

cryomodule, vacuum, alignment, solenoid

511

J. Bernardini, C. Boffo, M. Chen, J. Helsper, M. Kramp, F.L. Lewis, T.H. Nicol, M. Parise, D. Passarelli, V. Roger, G.V. Romanov, B. Squires, M. Turenne
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Fermi Research Alliance, LLC under Contract No. DEAC02- 07CH11359 with the United States Department of Energy, Office of Science, Office of High Energy Physics.
The present contribution reports the design of the pre-production Single Spoke Resonator Type 2 Cryomodule (ppSSR2 CM), developed in the framework of the PIP-II project at Fermilab. The innovative design is based on a structure, the strongback, which supports the coldmass from the bottom, stays at room temperature during operations, and can slide longitudinally with respect to the vacuum vessel. The Fermilab style cryomodule developed for the prototype Single Spoke Resonator Type 1 (pSSR1) and the prototype High Beta 650 MHz (pHB650) cryomodules is the baseline of the current design, which paves the way for production SSR1 and SSR2 cryomodules for the PIP-II linac. The focus of this contribution is on the results of calculations and finite element analysis performed to optimize the critical components of the cryomodule: vacuum vessel, strongback, thermal shield, and magnetic shield.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE12

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Received ※ 24 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 02 September 2022

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TUPOGE13

Niobium to Titanium Electron Beam Welding for SRF Cavities

niobium, SRF, vacuum, linac

515

M. Parise, J. Bernardini, D. Passarelli
Fermilab, Batavia, Illinois, USA

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
Titanium and niobium are the main materials used for the fabrication of Superconducting Radio Frequency (SRF) cavities. These two metals are usually joined , using various welding techniques, using a third material in between. This contribution focuses on the development of an innovative electron beam welding technique capable of producing a strong bond between these two different materials. Several samples are produced and tested to assess the mechanical strength at room and cryogenic temperature as well as the composition of the resulting welded joint. Also, the first units of the Single Spoke Resonator type 2 (SSR2) cavities for the Proton Improvement Plan-II (PIP-II [1]) have been fabricated joining directly various grades of titanium to niobium and results gathered through the fabrication will be reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE13

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Received ※ 14 August 2022 — Revised ※ 17 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 02 September 2022

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TUPOGE14

Beamline Volume Relief Analysis for the PIP-II SSR2 Cryomodule at Fermilab

cryomodule, SRF, vacuum, radiation

519

M. Parise, J. Bernardini, D. Passarelli
Fermilab, Batavia, Illinois, USA

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
The beam volume of the Pre-Production Single Spoke Resonator type 2 (ppSSR2) cryomodule [1] for the Proton Improvement Plan-II (PIP-II) [2] project will be protected against over-pressurization using a burst disk. This contri- bution focuses on the analysis of the relief of such trapped volume during a catastrophic scenario with multiple systems failures. An analytical model, able to predict the pressure in the beam volume depending of the various boundary condi- tions, has been developed and will be presented along with the results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE14

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Received ※ 24 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 02 September 2022

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TUPOGE16

Standardization and First Lessons Learned of the Prototype HB650 Cryomodule for PIP-II at Fermilab

cryomodule, vacuum, interface, SRF

526

V. Roger, J. Bernardini, S.K. Chandrasekaran, C.J. Grimm, O. Napoly, J.P. Ozelis, M. Parise, D. Passarelli
Fermilab, Batavia, Illinois, USA
N. Bazin, R. Cubizolles
CEA-IRFU, Gif-sur-Yvette, France

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
The prototype High Beta 650 MHz cryomodule (pHB650 CM) has been designed by an integrated design team, consisting of Fermilab (USA), CEA (France), STFC UKRI (UK), and RRCAT (India). The manufacturing and assembly of this prototype cryomodule is being done at Fermilab, whereas the production cryomodules will be manufactured and assembled by STFC-UKRI. As the first PIP-II cryomodule for which standardization was applied, the design, manufacturing and assembly of this cryomodule led to significant lessons being learnt and experiences gathered. These were incorporated into the design of the pre-production Single Spoke Resonator Type 2 cryomodule (ppSSR2 CM) and the pre-production Low Beta 650 MHz cryomodule (ppLB650 CM). This paper presents the pHB650 CM lessons learned and experiences gathered from the design to the lower coldmass assembly and how this cryomodule has a positive impact on all the next Proton Improvement Plan-II (PIP-II) cryomodules due to the standardization set up among SSR and 650 cryomodules.

Poster TUPOGE16 [1.478 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE16

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Received ※ 11 August 2022 — Revised ※ 17 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 15 September 2022

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TUPOGE17

Fabrication Experience of the Pre-Production PIP-II SSR2 Cavities at Fermilab

niobium, operation, SRF, target

529

M. Parise, D. Passarelli, V. Roger
Fermilab, Batavia, Illinois, USA
P. Duchesne, D. Longuevergne
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
The Proton Improvement Plan-II (PIP-II, [1]) linac will in- clude 35 Single Spoke Resonators type 2 (SSR2). A total of eight pre-production SSR2 jacketed cavities will be procured and five installed in the first pre-production cryomodule. The mechanical design of the jacketed cavity has been finalized and it will be presented in this paper along with fabrication and processing experience. The importance of interfaces, quality controls and procurement aspects in the design phase will be remarked as well as lessons learned during the fabri- cation process. Furthermore, development studies will be presented together with other design validation tests.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE17

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Received ※ 14 August 2022 — Revised ※ 16 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 04 September 2022

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TUPOGE18

Operations of Copper Cavities at Cryogenic Temperatures

cryogenics, vacuum, coupling, experiment

533

H. Wang, U. Ratzinger, M. Schuett
IAP, Frankfurt am Main, Germany

This work is focused on the anomalous skin effect in copper and how it affects the efficiency of copper-cavities in the temperature range 40-50 K. The quality factor Q of three coaxial cavities was measured over the temperature range from 10 K to room temperature in the experiment. The three coaxial cavities have the same structure, but different lengths, which correspond to resonant frequencies: around 100 MHz, 220 MHz and 340 MHz. Furthermore, the effects of copper-plating and additional baking in the vacuum oven on the quality factor Q are studied in the experiment. The motivation is to check the feasibility of an efficient, pulsed, ion linac, operated at cryogenic temperatures.

Slides TUPOGE18 [1.115 MB]

Poster TUPOGE18 [1.518 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE18

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Received ※ 22 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 03 September 2022

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TUPOGE19

Status of the New Intense Heavy Ion DTL Project Alvarez 2.0 at GSI

DTL, quadrupole, focusing, operation

537

L. Groening, T. Dettinger, X. Du, M. Heilmann, M. Kaiser, E. Merz, S. Mickat, A. Rubin, C. Xiao
GSI, Darmstadt, Germany

The Alvarez-type post-stripper DTL at GSI accelerates intense ion beams with A/q <= 8.5 from 1.4 to 11.4 MeV/u. After more than 45 years of operation it suffers from aging and its design does not meet the requirements of the upcoming FAIR project. The design of a new 10⁸ MHz Alvarez-type DTL has been completed and series components for the 55 m long DTL are under production. In preparation, a first cavity section as First of Series has been operated at nominal RF-parameters. Additionally, a prototype drift tube with internal pulsed quadrupole has been built and operated at nominal parameters successfully. High quality of copper-plating of large components and add-on parts has been achieved within the ambitious specifications. This contribution summarizes the current project status of Alvarez 2.0 at GSI and sketches the future path to completion.

Slides TUPOGE19 [1.197 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE19

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Received ※ 18 August 2022 — Revised ※ 30 August 2022 — Accepted ※ 08 September 2022 — Issue date ※ 15 September 2022

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TUPORI04

Cavity Failure Compensation Strategies in Superconducting Linacs

linac, cryomodule, database, lattice

552

A. Plaçais, F. Bouly
LPSC, Grenoble Cedex, France

RF cavities in linear accelerators are subject to failure, preventing the beam from reaching it’s nominal energy. This is particularly problematic for Accelerator Driven Systems (ADS), where the thermal fluctuations of the spallation target must be avoided and every fault shall be rapidly compensated for. In this study we present LightWin. This tool under development aims to create a database of the possible cavity failures and their associated compensation settings for a given accelerator. We apply it on the MYRRHA ADS, with a scenario including various faults distributed along the accelerator, and compare the settings found by LightWin to those found by the code TraceWin. We show that both tools find different compensation settings. We also outline the limitations of LightWin and explain the upcoming improvements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPORI04

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Received ※ 23 August 2022 — Revised ※ 20 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 11 September 2022

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TUPORI05

Beam Dynamic Simulations for the DTL Section of the High Brilliance Neutron Source

linac, neutron, emittance, quadrupole

556

S. Lamprecht, M. Droba, K. Kümpel, O. Meusel, N.F. Petry, H. Podlech, M. Schwarz, C. Zhang
IAP, Frankfurt am Main, Germany

As various experimental reactors in Europe are already or will be decommissioned over the next years, new neutron sources will be necessary to meet the demand for neutrons in research and development. The High Brilliance Neutron Source is an accelerator driven neutron source planned at the Forschungszentrum Jülich. The accelerator will accelerate a proton beam of 100 mA up to an end energy of 70 MeV, using 45 normal conducting CH-type cavities. Due to the high beam current, the beam dynamics concept requires special care. In this paper, the current status of the beam dynamics for the drift tube linac is presented.

Poster TUPORI05 [0.917 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPORI05

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Received ※ 23 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 01 September 2022

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TUPORI06

Harmonic Bunch Formation and Optional RFQ Injection

rfq, emittance, space-charge, injection

559

E. Sunar, U. Ratzinger, M. Syha, R. Tiede
IAP, Frankfurt am Main, Germany

With the aim of reduced beam emittances, a pre-bunching concept into an RFQ or a DTL has been developed. The structure has been designed by using a two harmonics double drift buncher which consists of two bunchers: the first one is driven by a fundamental frequency whereas the other is ex- cited with the second harmonic including a drift in between. This well-known "Harmonic Double-Drift-Buncher" is rein- vestigated under space charge conditions for RFQ, cyclotron, and for direct DTL-injection. There are significant benefits for this design such as to catch as many particles as possible from a dc beam into the longitudinal linac acceptance, or to reduce/optimize by up to an order of magnitude the lon- gitudinal emittance for low and medium beam currents. In accordance to these advantages, a new multi-particle track- ing beam dynamics code has been developed which is called "Bunch Creation from a DC beam - BCDC". In this paper we present this new code and some stimulating examples.

Poster TUPORI06 [28.234 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPORI06

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Received ※ 14 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 05 September 2022

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TUPORI13

Beam Loading Simulation for Relativistic and Ultrarelativistic Beams in the Tracking Code RF-Track

beam-loading, simulation, accelerating-gradient, linac

569

J. Olivares Herrador, A. Latina
CERN, Meyrin, Switzerland
D. Esperante Pereira, N. Fuster, B. Gimeno
IFIC, Valencia, Spain
B. Gimeno
UVEG, Burjasot (Valencia), Spain

Medical and industrial electron linacs can benefit from the X-band accelerating technology developed for the Compact Linear Collider (CLIC) at CERN. However, when high-intensity beams are injected in such high-gradient structures (>35 MV/m), the beam loading effect must be considered by design since this beam-cavity interaction can result in a considerable gradient reduction with respect to the unloaded case. Studying energy conservation, a partial differential equation (PDE) has been derived for injected beams, in both the relativistic and ultrarelativistic limit. Making use of this, a specific simulation package within RF-track has been developed, allowing realistic tracking of charged particle bunches under this effect regardless of their initial velocity. The performance of such tool has been assessed by reproducing previously obtained beam loaded fields in CLIC main linac and CLIC Drive-Beam linac structures. In this paper we present the analytic PDE derivation and the results of the tests.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPORI13

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Received ※ 18 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 07 September 2022

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TUPORI16

The PSI Positron Production Project

positron, solenoid, emittance, electron

577

N. Vallis, B. Auchmann, P. Craievich, M. Duda, H. Garcia Rodrigues, J. Kosse, F. Marcellini, M. Schaer, R. Zennaro
PSI, Villigen PSI, Switzerland

Funding: CHART (Swiss Accelerator Research and Technology)
The PSI Positron Production project (P³ or P-cubed) is a demonstrator for a novel positron source for FCC-ee. The high current requirements of future colliders can be compromised by the extremely high positron emittance at the production target and consequent poor capture and transport to the damping ring. However, recent advances in high-temperature superconductors allow for a highly efficient matching of such an emittance through the use a solenoid around the target delivering a field over 10 T on-axis. Moreover, the emittance of the matched positron beam can be contained through large aperture RF cavities surrounded by a multi-Tesla field generated by conventional superconducting solenoids, where simulations estimate a yield higher by one order of magnitude with respect to the state-of-the-art. The goal of P³ is to demonstrate this basic principle by implementing the aforementioned solenoids into a prototype positron source based on a 6 GeV electron beam from the SwissFEL linac, two RF capture cavities and a beam diagnostics section.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPORI16

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Received ※ 15 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 09 September 2022

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TUPORI19

Beam Dynamics Framework Incorporating Acceleration Used to Define the Minimum Aperture of RF Cavity For FODO-like Focusing Scheme for Proton Radiotherapy Linac

quadrupole, acceleration, focusing, lattice

589

M.J.W. Southerby, R. Apsimon
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

Funding: Supported by the Cockcroft Institute Core Grant, ST/P002056/1.
In this paper, we present a generalised analytical framework for beam dynamics studies and lattice designs, while incorporating longitudinal acceleration of bunches of charged particles. We study a ’FODO-like’ scheme, whereby we have an alternating array of focusing and defocusing quadrupoles and study how this differs from a standard FODO lattice due to acceleration. We present optimisation techniques to provide quadrupole parameters, cavity lengths, and required drift lengths under different constraints.

Poster TUPORI19 [0.997 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPORI19

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Received ※ 23 August 2022 — Revised ※ 27 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022

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TUPORI20

The Impact of Beam Loading Transients on the RF System and Beam Breakup Instabilities in Energy Recovery Linacs

beam-loading, simulation, linac, LLRF

593

S. Setiniyaz
Lancaster University, Lancaster, United Kingdom
R. Apsimon, M.J.W. Southerby
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

In multi-turn Energy Recovery Linacs (ERLs), the filling pattern describes the order that which bunches are injected into the ERL ring. The filling patterns and recombination schemes together can create various beam loading patterns/transients, which can have a big impact on the RF system, namely the cavity fundamental mode voltage, required RF power, and beam breakup instability. In this work, we demonstrate one can lower the cavity voltage fluctuation and rf power consumption by carefully choosing the right transient by using an analytical model and simulation.

Poster TUPORI20 [0.659 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPORI20

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Received ※ 19 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 31 August 2022

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TUPORI26

Longitudinal Beam Dynamics in Array of Equidistant Multicell Cavities

linac, acceleration, emittance, space-charge

609

Y.K. Batygin
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by US DOE under contract 89233218CNA000001
Linear accelerators containing the sequence of independently phase cavities with constant geometrical velocity along each cavity are widely used in practice. The chain of cavities with identical cell length is utilized within a certain beam velocity range, with subsequent transformation to the next chain with higher cavity velocity. Design and analysis of beam dynamics in this type of accelerators are usually performed using numerical simulations. In the present paper, we provide an analytical treatment of beam dynamics in such linacs. Expressions connecting beam energy gain and phase slippage along the cavity are implemented. The dynamics of the beam around the reference trajectory along the accelerator and matched beam conditions are discussed.

Poster TUPORI26 [1.718 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPORI26

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Received ※ 20 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 02 September 2022

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TH1AA02

Developments Towards FRIB Upgrade to 400 MeV/u for Heaviest Uranium Ions

background, cryomodule, ECR, linac

653

K.E. McGee, K. Elliott, A. Ganshyn, W. Hartung, S.H. Kim, P.N. Ostroumov, J.T. Popielarski, L. Popielarski, A. Taylor, T. Xu
FRIB, East Lansing, Michigan, USA
G.V. Eremeev, F. Furuta, M. Martinello, O.S. Melnychuk, A.V. Netepenko
Fermilab, Batavia, Illinois, USA
B.M. Guilfoyle, M.P. Kelly, T. Reid
ANL, Lemont, Illinois, USA

High-Q₀ medium-velocity (beta opt = 0.6) 5-cell elliptical cavities for superconducting linacs are critical technology for advancing current and future projects such as the Proton Improvement Plan II linac and the proposed energy upgrade of Michigan State University’s Facility For Rare Isotope Beams linac, FRIB400. Previous work established the validity of the novel geometry of the FRIB400 prototype 644 MHz 5-cell elliptical β = 0.65 cavities for future high Q₀ development. In collaboration with FNAL, two leading-edge high-Q₀ recipes, N-doping and Mid-T baking, were tested in the 5-cell format. 2/0 N-doping + cold electropolishing was successful at achieving FRIB400 and PIP-II Q₀ requirements, achieving an unprecedented 3.8 x 10¹⁰ at 17.5 MV/m, satisfying the FRIB400 Q₀ requirements by 1.75 times in a low-gauss environment. Mid-T baking exceeded FRIB400 Q₀ requirements by 1.4 times, and benefitted from decreased residual resistance compared to the N-doped cavity test. Systematic ultrasonic thickness measurements in single-cell revealed bulk (150 microns) EP with the modified EP tool is consistent across the inner surfaces of the cavity walls.

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Slides TH1AA02 [44.708 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TH1AA02

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Received ※ 11 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 23 September 2022 — Issue date ※ 14 October 2022

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TH1AA06

Low Level RF Control Algorithms for the CERN Proton LINAC4

linac, LLRF, klystron, beam-loading

673

P. Baudrenghien, B. Bielawski, R.B. Borner
CERN, Meyrin, Switzerland

The CERN Linac4 Low Level RF (LLRF) uses a Linear Gaussian Regulator and an Adaptive Feed Forward to regulate the accelerating field in the cavities in the presence of strong beam loading. A Klystron Polar Loop is also implemented to compensate the RF perturbations caused by the ripples and droop in the klystron High Voltage supply. The talk presents the important parts of the regulation, shows results as the system has evolved from first prototype (2013) to operational beams (2020), and mentions some important issues encountered during the commissioning and the first years of operation, with their mitigations.

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Slides TH1AA06 [4.183 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TH1AA06

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Received ※ 24 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 06 September 2022

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TH1PA02

Production, Test and Installation of the ESS Spoke, Medium and High Beta Cryomodules

cryomodule, operation, linac, MMI

685

C.G. Maiano
ESS, Lund, Sweden

We present here an overview of the ESS cryomodule production, test and preparation to tunnel installation, covering both families of modules: spoke and elliptical. Cryomodules and cavities for the ESS linac are in-kind contribution by several of the project partners.

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Slides TH1PA02 [2.190 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TH1PA02

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Received ※ 23 August 2022 — Revised ※ 30 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 02 September 2022

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THPOJO03

RF Performance of a Next-Generation L-Band RF Gun at PITZ

gun, vacuum, electron, FEL

699

M. Krasilnikov, Z. Aboulbanine, G.D. Adhikari, N. Aftab, P. Boonpornprasert, M.E. Castro Carballo, G.Z. Georgiev, J. Good, M. Groß, A. Hoffmann, C. Koschitzki, X.-K. Li, A. Lueangaramwong, D. Melkumyan, R. Niemczyk, A. Oppelt, B. Petrosyan, S. Philipp, M. Pohl, H.J. Qian, C.J. Richard, J. Schultze, F. Stephan, G. Vashchenko, T. Weilbach
DESY Zeuthen, Zeuthen, Germany
M. Bousonville, F. Brinker, M. Hoffmann, K. Knebel, D. Kostin, S. Lederer, L. Lilje, S. Pfeiffer, R. Ritter, S. Schreiber, H. Weise, J. Ziegler
DESY, Hamburg, Germany
G. Shu
IHEP, Beijing, People’s Republic of China
M. Wenskat
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

A new generation of normal conducting 1.3GHz RF gun was developed to provide a high-quality electron source for superconducting linac driven free-electron lasers like FLASH and European XFEL. Compared to the Gun4 series, Gun5 aims for a 50% increase of the duration of the RF pulse (up to 1 ms at 10 Hz repetition rate) combined with high gradients (up to ~60 MV/m at the cathode). In addition to the improved impedance, the new cavity is equipped with an RF probe to measure and control the amplitude and phase of the RF field inside the gun. The first prototype of the new RF gun was manufactured at DESY and installed at the Photo Injector Test facility at DESY in Zeuthen (PITZ) in October 2021. In mid-October 2021 the RF conditioning began, aiming for achieving the aforementioned RF parameters. The conditioning procedure involves a slow gradual increase in repetition rate, RF pulse duration and peak power while carefully monitoring vacuum conditions and signals from interlock sensors. The results of RF conditioning will be reported.

Poster THPOJO03 [2.241 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOJO03

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Received ※ 26 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 03 September 2022 — Issue date ※ 15 September 2022

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THPOJO10

RF Design and Characterisation of the CLARA 10 Hz Gun with Photocathode Load/Lock Upgrade

cathode, gun, simulation, vacuum

715

A.J. Gilfellon, L.S. Cowie, T.J. Jones, B.L. Militsyn, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The 2.5 cell S-band 10 Hz repetition rate electron gun (Gun-10) for the CLARA (Compact Linear Accelerator for Research and Applications) facility underwent an upgrade during the scheduled shutdown period during the summer of 2019. The existing photocathode/back plate was replaced by a new back plate with interchangeable photocathode socket connected to a load/lock system capable of rapid exchanges of photocathode plugs. Here we outline motivation and RF design of the back plate and also detail the low power RF testing and characterisation of the upgraded gun in terms of the unloaded quality factor, the RF power coupling match, the percent field flatness and the operating frequency of the cavity, calculated from the frequency measured in the laboratory. Finally, via simulations using CST MWS and ASTRA, we produce a dependence of expected beam momentum vs forward power that we predict the gun will deliver once it goes back online.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOJO10

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Received ※ 25 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 16 September 2022

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THPOJO12

LCLS-II-HE Cryomodule Testing at Fermilab

cryomodule, radiation, operation, plasma

721

A.T. Cravatta, T.T. Arkan, D. Bafia, B.E. Chase, M. Checchin, C. Contreras-Martinez, B. Giaccone, B.J. Hansen, E.R. Harms, B.D. Hartsell, J.A. Kaluzny, D.D. Lambert, J.N. Makara, H. Maniar, M. Martinello, Y.M. Pischalnikov, S. Posen, J. Reid, N. Solyak, D. Sun, A. Syed, R. Wang, M.J. White, G. Wu
Fermilab, Batavia, Illinois, USA
S. Aderhold, A.L. Benwell, J.D. Fuerst, D. Gonnella, T. Hiatt, S.L. Hoobler, J.T. Maniscalco, J. Nelson, L.M. Zacarias
SLAC, Menlo Park, California, USA
L.R. Doolittle, S. Paiagua, C. Serrano
LBNL, Berkeley, California, USA

22 Linac Coherent Light Source II (LCLS-II) cryomodules were successfully tested at the Cryomodule Test Facility (CMTF) at Fermilab. Following the completion of the LCLS-II testing program, CMTF has shifted to testing cryomodules for the LCLS-II High Energy upgrade (LCLS-II-HE). The first LCLS-II-HE cryomodule, the verification cryomodule (vCM), was successfully tested and verified the readiness of LCLS-II-HE cryomodule testing at CMTF, and production cryomodule testing has begun. Presented here are the production cryomodule test acceptance criteria, testing plan, and cryomodule test results so far.

Poster THPOJO12 [0.899 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOJO12

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Received ※ 18 August 2022 — Revised ※ 27 August 2022 — Accepted ※ 06 September 2022 — Issue date ※ 15 September 2022

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THPOJO14

Distributed Coupling Linac for Efficient Acceleration of High Charge Electron Bunches

coupling, linac, distributed, electron

724

A. Dhar, M. Bai, Z. Li, E.A. Nanni, M.A.K. Othman, S.G. Tantawi, G.R. White
SLAC, Menlo Park, California, USA

Funding: This work was supported by the Department of Energy Contract No. DE-AC02-76SF00515.
The Electron Ion Collider requires a pre-injector linac to accelerate large electron bunches from 4 MeV up to 400 MeV over 35 m*. Currently this linac is being designed with 3 m long traveling wave structures, which provide a gradient of 16 MV/m. We propose the use of a 1 m distributed coupling design as a potential alternative and future upgrade path to this design. Distributed coupling allows power to be fed into each cavity directly via a waveguide manifold, avoiding on-axis coupling**. A distributed coupling structure at S-band was designed to optimize for shunt impedance and large aperture size. This design provides greater efficiency, thereby lowering the number of klystrons required to power the full linac. In addition, particle tracking analysis shows that this linac maintains lower emittance as bunch charge increases to 14 nC and wakefields become more prevalent. We present the design of this distributed coupling structure, as well as progress on structure manufacturing and characterization.
* F. Willeke, "Electron ion collider conceptual design report 2021," tech. rep., United States, 2021.
** S. Tantawi et al., Phys. Rev. Accel. Beams, vol. 23, p. 092001, Sep 2020.

Poster THPOJO14 [5.280 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOJO14

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Received ※ 24 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 15 September 2022

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THPOJO16

High Efficiency Traveling Wave Linac With Tunable Energy

linac, gun, electron, GUI

727

V.A. Dolgashev, A.K. Krasnykh, A. Romero
SLAC, Menlo Park, California, USA
P. Borchard
Dymenso LLC, San Francisco, USA
R.A. Kostin, S.V. Kuzikov
Euclid TechLabs, Solon, Ohio, USA

Funding: US DOE Research Opportunities in Accelerator Stewardship DE-FOA-0002463
We will present a physics design of a compact, highly efficient, energy-tunable linac to generate up to 500 W of 10 MeV electron beam power for medical and security applications. This linac will employ a patented travelling wave accelerating structure with outside power flow which combines the advantages of high efficiency with energy tunability of traveling wave cavities. Unlike standing wave structures, the proposed structure has little power reflected back to the RF source, eliminating the need for a heavy, lossy waveguide isolator. In contrast to the side-coupled cavity designs, the proposed structure is symmetrical and therefore it does not have deflecting axial fields that impair the beam transport. The high shunt impedance will allow the linac to achieve an output energy of up to 10 MeV when powered by a compact commercial 9.3 GHz 1.7 MW magnetron. For pulse-to-pulse tuning of the beam output energy we will change of the beam-loaded gradient by varying the triode gun current.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOJO16

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Received ※ 30 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 07 September 2022 — Issue date ※ 16 September 2022

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THPOJO21

Higher Order Modes Investigation in the PERLE Superconducting RF Cavity

HOM, damping, impedance, dipole

731

C. Barbagallo, P. Duchesne, W. Kaabi, G. Olry, Z.F. Zomer
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
R.A. Rimmer, H. Wang
JLab, Newport News, Virginia, USA

The regenerative Beam Break Up (BBU) excited by the dipole Higher Order Modes (HOMs) in superconducting RF (SRF) cavities is a crucial issue for continuous-wave high-current energy recovery linacs. Beam-induced monopole HOMs can increase the cryogenic losses of the linac also. One of the ways to limit these effects is to use HOM couplers on the beam tubes of cavities to absorb and untrap cavity eigenmodes. These couplers feature antennas designed to damp dangerous HOMs and adequately reject the fundamental mode. This study illustrates an investigation of the HOMs of a 5-cell 801.58 MHz elliptical SRF cavity designed for PERLE (Powerful Energy Recovery Linac for Experiments), a multi-turn energy recovery linac (ERL) currently under study and later to be hosted at IJCLab in Orsay. Time-domain wakefield and frequency-domain eigenmode simulations have been used to calculate the cavity broadband HOM impedance spectra and identify the dangerous BBU HOMs. The transmission characteristics of several coaxial HOM couplers have been studied. The efficiencies of several HOM-damping schemes have been compared to propose a HOM endgroup to be fabricated and added to the existing bare SRF cavity.

Poster THPOJO21 [2.090 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOJO21

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Received ※ 24 August 2022 — Revised ※ 27 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 23 September 2022

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THPOJO25

HOM Damping in Multi-Cell Superconducting Cavities for the Future Electron Source BriXSinO

HOM, linac, impedance, damping

739

S. Samsam, A. Bacci, C. Curatolo, I. Drebot, D. Giove, V. Petrillo, M. Rossetti Conti, A.R. Rossi, L. Serafini
INFN-Milano, Milano, Italy
A. Bosotti, D. Giove, L. Monaco, R. Paparella, D. Sertore
INFN/LASA, Segrate (MI), Italy
M.R. Masullo, A. Passarelli
INFN-Napoli, Napoli, Italy
V. Petrillo
Universita’ degli Studi di Milano, Milano, Italy

High order modes (HOMs) in multi-cell superconducting cavities are of particular concern in beam dynamics of linear accelerators, mainly those operating in CW mode with high current and high repetition rate. These undesired modes may invoke beam instabilities, beam breakup and increase the energy spread if not correctly pulled out and damped. The study reported in this paper is applied for damping the HOMs in the main Linac of BriXSinO, an ongoing project of an Energy Recovery Linac at LASA INFN laboratory. We developed a numerical model to study the interaction of monopole HOMs with the beam in long timescale. The presented model, named HOMEN (High Order Modes Evolution based on eNergy budget), allows the evaluation of the loss factor Kloss, crucial for evaluating the perturbing modes. At the same time, electromagnetic simulations of the standing wave multicell cavity, highlighted the dangerous modes and revealed a tolerable beam energy spread induced by HOMs. This method allows us to distinguish all dangerous modes of our interest for implementing the necessary damping mechanisms.

Poster THPOJO25 [1.111 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOJO25

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Received ※ 22 August 2022 — Revised ※ 17 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 15 September 2022

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THPOPA01

FLASH2020+ Upgrade - Modification of RF Power Waveguide Distribution for the Free-electron Laser FLASH at DESY

GUI, cryomodule, klystron, FEL

747

B. Yildirim, S. Choroba, V.V. Katalev, P. Morozov, Y. Nachtigal, N.V. Vladimirov
DESY, Hamburg, Germany

The goal of FLASH2020+ upgrade is to increase the energy of the FLASH accelerator, which allows the use of even shorter wavelengths, which, in turn, will allow new research. For this purpose, during the shutdown in 2022, two superconducting accelerator modules for ACC2 and ACC3 will be replaced by new ones. To fully realize the potential of these cryomodules XFEL type of waveguide distributions will be installed on them. In addition, the existing ACC4 and ACC5 cryomodules will also be equipped with the new waveguide distributions, similar XFEL type. These waveguide distributions will be modified and improved so that the machine can operate with the maximum energy due to individual power supply for each cavity. Furthermore, three RF stations will receive a new klystron waveguide distribution, which will improve the reliability of all systems. The specific waveguide distributions have been developed, produced and tested at the Waveguide Assembly and Test Facility (WATF) at DESY. All together will lead to increasing the electron beam energy from 1.25 to 1.35 GeV. This paper presents data on the production and tuning of waveguide distribution systems for the FLASH2020+ upgrade at DESY.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA01

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Received ※ 16 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 02 September 2022

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THPOPA12

Development and Integration of a New Low-Level RF System for MedAustron

controls, LLRF, synchrotron, hardware

764

M. Wolf, M. Cerv, C. Kurfürst, G. Muyan, S. Myalski, M. Repovž, C. Schmitzer
EBG MedAustron, Wr. Neustadt, Austria
A. Bardorfer, B. Baričevič, P. Paglovec, M. Škabar
I-Tech, Solkan, Slovenia

The MedAustron Ion Therapy Centre is a synchrotron-based particle therapy facility, which delivers proton and carbon beams for clinical treatments. Currently, the facility treats 40 patients per day and is improving its systems and workflows to further increase this number. Although MedAustron is a young and modern center, the life-cycle of certain crucial control electronics is near end-of-life and needs to be addressed. This paper presents the 216MHz injector Low-Level Radio Frequency (iLLRF) system with option of use for the synchrotron Low-Level Radio Frequency (sLLRF - 0.4-10MHz). The developed system will unify the cavity regulation for both LLRFs and will also be used for beam diagnostics (injector/synchrotron) and RF knock-out slow extraction. The new LLRF system is based on a µTCA platform which is controlled by the MedAustron Control System based on NI-PXIe. Currently, it supports fiberoptics links (SFP+), but other links (e.g. EPICS, DOOCS) can be established. The modular implementation of this LLRF allows connections to other components, such as motors, amplifiers, or interlock systems, and will increase the robustness and maintainability of the accelerator.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA12

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Received ※ 24 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 01 September 2022

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THPOPA13

Superconducting Cavity and RF Control Loop Model for the SPIRAL2 Linac

controls, linac, LLRF, feedback

767

F. Bouly
LPSC, Grenoble Cedex, France
M. Di Giacomo, J.F. Leyge, M. Tontayeva
GANIL, Caen, France

The SPIRAL2 superconducting linac has been successfully commissioned with protons in 2020. During the commissioning, a model of the cavity and its LLRF control loop has been developed. The model enables to have better understanding of the system and was used to guide the tuning of the PI(D) correctors for beam loading compensation. Here we review the development of such a tool, computed with MATLAB Simulink and using the frequency domain (Laplace transfer function) to model the cavity RF and mechanical behaviours (Lorentz detuning), as well as all elements that compose the RF control loop (digital LLRF, amplifier, transmission lines, etc.). The benchmarking of the model with measurement carried out with the proton beam is also discussed in this contribution.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA13

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Received ※ 24 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 03 September 2022 — Issue date ※ 15 September 2022

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THPOPA14

MTCA.4-Based LLRF System Prototype Status for MYRRHA

LLRF, operation, cryomodule, EPICS

771

C. Joly, S. Berthelot, N. Gandolfo, J. Rozé, J.-F. Yaniche
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
J-L. Bolli, I. Garcia, C. Gaudin
IOXOS Technologies, Gland, Switzerland
O. Bourrion, D. Tourres
LPSC, Grenoble Cedex, France
S. Boussa, W. De Cock, P. Della Faille, F. Pompon, E. Verhagen
SCK•CEN, Mol, Belgium

Within the framework of MINERVA, the first Phase of MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) project, IN2P3 labs are in charge of the development of several accelerator elements. Among those, a fully equipped Spoke cryomodule prototype was constructed. It integrates two superconducting single spoke cavities operating at 2K, the RF power couplers and the associated cold tuning systems. On the control side, a MTCA.4-based Low Level RadioFrequency (LLRF) system prototype has been implemented by IJCLab including FPGA specific firmware, a new µRTM frequency downconverter module from the company IOxOS Technologies and EPICS developments in collaboration with the SCK•CEN. The status of the LLRF system will be shown as well as its preliminary tests results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA14

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Received ※ 23 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 01 September 2022

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THPOPA15

Anomaly Detection Based Quench Detection System for CW Operation of SRF Cavities

experiment, SRF, operation, superconductivity

775

G. Martino, A. Bellandi, J. Branlard, A. Eichler, H. Schlarb
DESY, Hamburg, Germany
S. Aderhold, A.L. Benwell, D. Gonnella, S.L. Hoobler, J. Nelson, R.D. Porter, A. Ratti, L.M. Zacarias
SLAC, Menlo Park, California, USA
L.R. Doolittle
LBNL, Berkeley, California, USA
G. Fey
Hamburg University of Technology, Hamburg, Germany

Funding: This work is supported by DASHH (Data Science in Hamburg - HELMHOLTZ Graduate School for the Structure of Matter) under Grant No.: HIDSS-0002.
Superconducting radio frequency (SRF) cavities are used in modern particle accelerators to take advantage of their very high quality factor (Q). A higher Q means that a higher RF field can be sustained, and a higher acceleration can be produced in the cavity for length unity. However, in certain situations, e.g., too high RF field, the SRF cavities can experience quenches that risk creating damage due to the rapid increase in the heat load. This is especially negative in continuous wave (CW) operation due to the impossibility of the system to recover during the off-load period. The design goal of a quench-detection system is to protect the system without being a limiting factor during the operation. In this paper, we compare two different classification approaches for improving a quench detection system. We perform tests using traces recorded from LCLS-II and show that the ARSENAL classifier outperforms a CNN classifier in terms of accuracy.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA15

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Received ※ 24 August 2022 — Accepted ※ 25 August 2022 — Issue date ※ 23 September 2022

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THPOPA18

Development of a Tuner Control System for Low-Energy Superconducting Linac at RAON

controls, LLRF, EPICS, cryomodule

778

H. Kim, M.O. Hyun, H. Jang, M.S. Kim, Y. Kim
IBS, Daejeon, Republic of Korea

Funding: This research was supported by the RISP of ibs funded by the Ministry of Science and the National Research Foundation (NRF) of the Republic of Korea under Contract 2013M7A1A1075764.
We propose a tuner control system for low-energy superconducting linac at RAON. The frequency error of the superconducting cavities must be smaller than a few of Hz to operate in beam acceleration mode. To minimize the freuqency error as much as possible, the error is calculated in the low-level RF(LLRF), and the proposed tuner control system changes the superconducting cavity frequency by using a mechanical tuner and a motor attached to the cavity directly. This control system deals with not only the initial frequency error of the cavity but also the frequency drift of the cavity induced by external disturbance such as the slow fluctuation helium pressure automatically. In addition, an automatic proportional gain calibration technique is also proposed. In this paper, the detailed operation and techniques will be described.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA18

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Received ※ 13 August 2022 — Revised ※ 23 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 11 September 2022

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THPOPA19

Initial High Power RF Driving Test Using Digital LLRF for RF Conditioning of 1 MeV/n RFQ at KOMAC

rfq, LLRF, controls, experiment

781

H.S. Jeong, W.-H. Jung, D.-H. Kim, H.S. Kim, J.H. Kim, K.H. Kim, S.G. Kim, H.-J. Kwon, P. Lee, Y.G. Song
KOMAC, KAERI, Gyeongju, Republic of Korea

Funding: This work was supported through the KOMAC operation fund by the Ministry of Science and ICT of Korean government.
As a part of R&D toward the RFQ based heavy ion irradiation system, the 1 MeV/n RFQ was designed, brazed, installed and commissioned by staff researchers and engineers at KOMAC of KAERI. This 1 MeV/n RFQ system includes the microwave ion source, EBIS, RFQ, quadrupole magnets, switching magnet and the target systems. The digital based Low-Level RF was developed to provide the stable accelerating field to the RFQ. This Low-Level RF has features such as direct RF detection/generation without mixer, non-IQ sampling, PI feedback control, iterative learning based feed-forward control, and the digital RF interlock. In this paper, the characteristics of Low-Level RF are described, as well as the processes and results of an initial RF driving test for the RFQ’s RF conditioning.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA19

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Received ※ 22 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 15 September 2022

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THPOPA21

Narrow Bandwidth Active Noise Control for Microphonics Rejection in Superconducting Cavities at LCLS-II

controls, resonance, SRF, FPGA

785

A. Bellandi, J. Branlard
DESY, Hamburg, Germany
S. Aderhold, A.L. Benwell, A. Brachmann, J.A. Diaz Cruz, D. Gonnella, S.L. Hoobler, J. Nelson, A. Ratti, L.M. Zacarias
SLAC, Menlo Park, California, USA
J.A. Diaz Cruz
UNM-ECE, Albuquerque, USA
R.D. Porter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

LCLS-II is an X-Ray Free Electron Laser (XFEL) under commissioning at SLAC, being the first Continuous Wave (CW) hard XFEL in the world to come into operation. To accelerate the electron beam to an energy of 4 GeV, 280 superconducting cavities of the TESLA types are used. A Loaded Q (QL) value of 4x10⁷ is used to drive the cavities at a power level of a few kilowatts. For this QL value, the RF cavity bandwidth is equal to 32 Hz. Therefore, keeping the cavity resonance frequency within such bandwidth is imperative to avoid a significant increase in the required RF power. In superconducting accelerators, resonance frequency variations are produced by mechanical microphonic vibrations of the cavities. One source of microphonics noise is rotary machinery such as vacuum pumps or HVAC equipment. A possible method to reject these disturbances is to use Narrowband Active Noise Control (NANC) techniques. Such a technique was already tested at DESY/CMTB and Cornell/CBETA. This proceeding presents the implementation of a NANC controller in the LCLS-II Low Level RF (LLRF) control system. Tests on the rejection of LCLS-II microphonics disturbances are also presented.

Poster THPOPA21 [1.843 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA21

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Received ※ 24 August 2022 — Revised ※ 30 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 26 September 2022

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THPOPA24

First SELAP Algorithm Operational Experience of the New LLRF 3.0 RF Control System

LLRF, controls, operation, FPGA

795

T.E. Plawski, R. Bachimanchi, S. Higgins, C. Hovater, J. Latshaw, C.I. Mounts
JLab, Newport News, Virgina, USA

The JLAB LLRF 3.0 system has been developed and is replacing the 30-year-old LLRF systems in the CEBAF accelerator. The LLRF system builds upon 25 years of design and operational RF control experience (digital and analog), and our recent collaboration in the design of the LCLSII LLRF system. The new system also incorporates a cavity control algorithm using a fully functional phase and amplitude locked Self Exciting Loop (SELAP). The first system (controlling 8 cavities) was installed and commissioned in August of 2021. Since then the new LLRF system has been operating with cavity gradients up to 20 MV/m, and electron beam currents up to 350 uA. This paper discusses the operational experience of the LLRF 3.0 SELAP algorithm along with other software and firmware tools like cavity and klystron characterization and quench detection.
T. E. Plawski et al., ’JLAB LLRF 3.0 Development and Tests’, in Proc. 12th Int. Particle Accelerator Conf. (IPAC’21), Campinas, Brazil, May 2021, pp

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA24

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Received ※ 10 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 07 September 2022 — Issue date ※ 12 October 2022

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THPOPA26

Machine Learning Assisted Cavity Quench Identification at the European XFEL

FEL, operation, software, hardware

798

J. Branlard, A. Eichler, J.H.K. Timm, N. Walker
DESY, Hamburg, Germany

A server-based quench detection system is used since the beginning of operation at the European XFEL (2017) to stop driving superconducting cavities if they experience a quench. While this approach effectively detects quenches, it also generates false positives, tripping the accelerating stations when failures other than quenches occur. Using the post-mortem data snapshots generated for every trip, an additional signal (referred to as residual) is systematically computed based on the standard cavity model. Following an initial training on a set of such residuals derived from quench as well as non-quench events, two independent machine learning engines analyze routinely the trip snapshots and their residuals to identify if a trip was indeed triggered by a quench or has another root cause. The outcome of the analysis is automatically appended to the data snapshots and distributed to a team of experts. This constitutes a fully deployed example of machine-learning-assisted failure classification to identify quenches, supporting experts in their daily routine of monitoring and documenting the accelerator uptime and availability.

Slides THPOPA26 [0.695 MB]

Poster THPOPA26 [0.975 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA26

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Received ※ 19 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 01 September 2022

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THPOGE01

Study on the Multipactor Barriers of the SARAF-Phase 2 Low-Beta and High-Beta Superconducting Cavities

multipactoring, linac, MMI, superconducting-cavity

802

G. Ferrand, L. Maurice
CEA-IRFU, Gif-sur-Yvette, France
M. Baudrier, N. Pichoff
CEA-DRF-IRFU, France

CEA is committed to delivering a Medium Energy Beam Transfer line and a superconducting linac (SCL) for SARAF accelerator in order to accelerate 5 mA beam of either protons from 1.3 MeV to 35 MeV or deuterons from 2.6 MeV to 40 MeV. The SCL contains 13 half-wave resonator (HWR) low beta cavities (β= 0.09) at 176 MHz and 14 HWR high-beta cavities (β = 0.18) at 176 MHz. The low-beta and high-beta series were qualified in 2021 and 2022 respectively. This contribution will focus on the observation of the multipactor barriers for all cavi-ties. It will present series of data obtained during the conditioning of these cavities

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE01

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Received ※ 27 July 2022 — Revised ※ 23 August 2022 — Accepted ※ 07 September 2022 — Issue date ※ 15 September 2022

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THPOGE02

Investigation of HiPIMS-Coated S(I)S Structures for SRF Cavities

SRF, site, niobium, radio-frequency

805

A.Ö. Sezgin, X. Jiang, M. Vogel
University Siegen, Siegen, Germany
C.Z. Antoine
CEA-IRFU, Gif-sur-Yvette, France
S. Keckert, J. Knobloch, O. Kugeler, D.B. Tikhonov
HZB, Berlin, Germany
J. Knobloch
University of Siegen, Siegen, Germany
O.B. Malyshev
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
R. Ries, E. Seiler
Slovak Academy of Sciences, Institute of Electrical Engineering, Bratislava, Slovak Republic
L.G.P. Smith
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

The sustainable next generation particle accelerators require innovative solutions to overcome the current technological challenges set by existing bulk niobium superconducting radio-frequency (SRF) cavities. Thin film-based multilayer structures in the form of superconductor-insulator-superconductor (SIS) may be the long-sought-after breakthrough for higher performance SRF cavities by enhancing both accelerating gradients and quality factors. In order to understand better the underlying mechanisms of SIS structures to be coated onto (S)RF cavities, we study various material properties with the resultant superconducting properties of high-power im-pulse magnetron sputtering (HiPIMS)-coated S(I)S structures of Nb-(AlN)-NbN with different thicknesses which are designed to be coated mainly on OFHC copper (Cu) samples for more efficient SRF cavities. This contribution presents materials properties of the aforementioned HiPIMS-coated S(I)S structures as well as the superconducting and RF behaviours of these multilayers which are assessed comparatively via DC and AC magnetization techniques.

Poster THPOGE02 [0.747 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE02

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Received ※ 25 August 2022 — Revised ※ 30 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 02 September 2022

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THPOGE03

Design & Multiphysics Analysis of Three-cell, 1.3 GHz Superconducting RF Cavity for Electron Beam Accelerator to Treat Wastewater

electron, accelerating-gradient, multipactoring, HOM

809

P. Kumar, A. Pathak, R. Varma
IIT Mumbai, Mumbai, India

To treat industrial effluents including contaminants of emerging concern (CECs), Irradiation treatment by electron beam accelerator has shown promising results. Our aim is to design and develop a superconducting linear electron accelerator. A 1.3 GHz, three cell conduction cooled, TM class superconducting cavity has been proposed to accelerate a 100 mA electron beam from 100 keV to 4.5 MeV. The main aim of the design is to optimize the cavity for low heat loss and high accelerating gradient. The optimized ratio of peak surface electric and magnetic field to accelerating field for cavity are Epk/E_acc= 2.72 and Hpk/E_acc= 4.11 mT/(MV/m). The optimized Geometry factor (G) and R/Q values for this cavity are 246.7 and 306.4 ohms respectively. Here we also addressed other multiphysics issues such as Lorentz force detuning (LFD), Higher order modes (HOMs) and Multipacting. The multiphysics analysis helps to estimate the degree of these challenges. The final Lorentz detuning factor of the cavity has been reduced to 0.12 Hz/(MV/m)2, HOMs of 2.18 and 2.9 GHz modes are dominating except the main mode and Multipacting phenomena is not found at 15 MV/m of accelerating gradient.

Poster THPOGE03 [1.121 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE03

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Received ※ 22 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 14 October 2022

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THPOGE05

Some Interesting Observations During Vertical Test on ESS-HB-704 SRF Cavities

accelerating-gradient, operation, MMI, SRF

812

K.D. Dumbell, A.E.T. Akintola, R.K. Buckley, M.J. Ellis, S. Hitchen, P.C. Hornickel, C.R. Jenkins, J. Lewis, A.J. May, P.A. McIntosh, K.J. Middleman, A.J. Moss, S.M. Pattalwar, M.D. Pendleton, P.A. Smith, A.E. Wheelhouse, S. Wilde
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
M.D. Hancock, J. Hathaway, C. Hodgkinson, G. Jones, M. Lowe, D.A. Mason, G. Miller, J. Mutch, A. Oates, J.T.G. Wilson
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

The vertical test stand in use at Daresbury has three cavities loaded horizontally at different heights. The jacketed cavities are supplied with liquid helium from a header tank at the top of the configuration. A few cavities have been tested in different positions and the results have been analysed. The pressure of the helium inside the jacketed cavities is affected by the height of the liquid helium column above the jacket and using results from earlier analysis during cool-down enables the pressure of the cavity to be determined from the frequency of operation. Analysis of the effects may allow for corrections to the frequency to be made. In addition to the above observations there have also been some challenges in the operation at higher power as the phase of the self-excited loop driving the system, has been seen to change. This paper discusses some of the observation, analysis of those observations and challenges that are being addressed in the continuing use of this facility.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE05

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Received ※ 10 August 2022 — Revised ※ 13 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 15 September 2022

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THPOGE09

Split Thin Film SRF 6 GHz Cavities

niobium, SRF, cryogenics, ISOL

814

B.S. Sian, G. Burt, D.J. Seal
Lancaster University, Lancaster, United Kingdom
G. Burt, O.B. Malyshev, D.J. Seal, R. Valizadeh
Cockcroft Institute, Warrington, Cheshire, United Kingdom
O.B. Malyshev, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
H.S. Marks
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

Many current accelerators use cavities that are manufactured as two half cells that are electron beam welded together, the weld is across the peak surface current of the cavity. This weld can lead to large increases in surface resistance and limit the performance of thin film coated cavities. Many problems with the coating process for thin film Superconducting Radio Frequency (SRF) cavities are also due to this weld. Thin film SRF cavities can perform as well as bulk niobium cavities if the cavity is manufactured seamlessly, without any weld, as they have a more uniform surface, however, they are much more difficult and expensive to manufacture. A cavity with a split longitudinally, parallel to the direction of the electric field, would not need to be welded. These seamless cavities are easier to manufacture and coat. This opens the possibilities to coat with new materials and multilayer coatings. These cavities may allow SRF cavities to operate at significantly better parameters (higher quality factor and maximum accelerating field) than current state of the art cavities. This work discusses development and testing of longitudinally split seamless cavities at Daresbury Laboratory.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE09

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Received ※ 25 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 12 September 2022 — Issue date ※ 15 October 2022

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THPOGE10

RF Characterisation of Bulk Niobium and Thin Film Coated Planar Samples at 7.8 GHz

SRF, site, operation, superconducting-RF

818

D.J. Seal, G. Burt, O.B. Malyshev, B.S. Sian, R. Valizadeh
Cockcroft Institute, Warrington, Cheshire, United Kingdom
G. Burt, D.J. Seal, B.S. Sian
Lancaster University, Lancaster, United Kingdom
E. Chyhyrynets, C. Pira
INFN/LNL, Legnaro (PD), Italy
O. Hryhorenko, D. Longuevergne
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
O.B. Malyshev, E.A. Marshall, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
H.S. Marks
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

Research is ongoing into the use of superconducting thin films to replace bulk niobium for future radio frequency (RF) cavities. A key part of this research requires measuring the RF properties of candidate films. However, coating and testing thin films on full-sized cavities is both costly and time-consuming. Instead, films are typically deposited on small, flat samples and characterised using a test cavity. A cost-effective facility for testing such samples has recently been built and commissioned at Daresbury Laboratory. The facility allows for low power surface resistance measurements at a resonant frequency of 7.8 GHz, temperatures down to 4 K and sample surface magnetic fields up to 1 mT. A brief overview of this facility as well as recent results from measurements of both bulk Nb and thin film coated samples will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE10

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Received ※ 11 August 2022 — Revised ※ 19 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 16 September 2022

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THPOGE13

Design of Production PIP-II SSR1 Cavities

GUI, cryomodule, niobium, SRF

822

C.S. Narug, J. Bernardini, M. Parise, D. Passarelli
Fermilab, Batavia, Illinois, USA

Funding: Work supported by the Fermi National Accelerator Laboratory, managed and operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
The testing and manufacturing process of the PIP-II Single Spoke Resonators Type 1 (SSR1) prototype jacketed cavity presented opportunities for refinement of the production series. Experience from the prototype cavity and the design of other cavities at Fermilab were used. The mechanical design of the production jacketed cavity has been modified from the prototype design to allow for improvements in overall performance, structural behavior, and manufacturability of the weld joints.

Poster THPOGE13 [1.199 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE13

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Received ※ 14 August 2022 — Revised ※ 23 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 02 September 2022

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THPOGE16

Evaluation of Single-Cell Cavities Made of Forged Ingot Niobium at Jefferson Lab

SRF, niobium, radio-frequency, cryomodule

828

P. Dhakal, G. Ciovati, G.R. Myneni
JLab, Newport News, Virginia, USA
G. Ciovati, B.D. Khanal
ODU, Norfolk, Virginia, USA
G.R. Myneni
BSCE, Yorktown, Virginia, USA

Funding: This manuscript has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Currently, fine grain niobium (Nb) (grain size ~ 50 um) and large grain Nb (grain size of a few cm) are being used for the fabrication of superconducting radio frequency (SRF) cavities. Medium grain forged ingot with grain size of a few hundred um may be beneficial for cost-effectiveness as well as providing better performance for future SRF-based accelerators. Forged ingot Nb with medium grain size is a novel production method to obtain Nb discs used for the fabrication of superconducting radio frequency cavities. We have fabricated two 1.5 GHz single cell cavities made from forged Nb ingot with a residual resistivity ratio of ~100. The cavities were chemically and mechanically polished and heat-treated in the temperature range of 650-1000 C before the rf test. One of the cavities reached an accelerating gradient of 34 MV/m with a quality factor Q > 1e10, while the second cavity was limited at 14 MV/m, likely due to a weld defect at the equator.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE16

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Received ※ 22 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 03 September 2022 — Issue date ※ 15 September 2022

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THPOGE18

Design of a 1.3 GHz RF-Dipole Crabbing Cavity for International Linear Collider

HOM, dipole, electron, collider

832

S.U. De Silva, J.R. Delayen
ODU, Norfolk, Virginia, USA
R.A. Rimmer
JLab, Newport News, Virginia, USA

The International Liner Collider (ILC) requires crabbing systems to increase the luminosity of the colliding electron and positron bunches. There are several frequency options for the crabbing cavity. We have designed a 1.3 GHz compact 1-cell and 2-cell rf-dipole crabbing cavity to compensate for luminosity degradation due to large crossing angle. This paper presents the 1-cell and 2-cell cavities designed to meet the current specifications including the fundamental power coupler and higher order mode couplers.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE18

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Received ※ 11 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 16 September 2022

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THPOGE19

Field Shielding of NbTiN Based Multilayer Structure for Accelerating Cavities

niobium, SRF, site, shielding

836

I.H. Senevirathne, J.R. Delayen, A.V. Gurevich
ODU, Norfolk, Virginia, USA
D.R. Beverstock
The College of William and Mary, Williamsburg, Virginia, USA
D.R. Beverstock, J.R. Delayen, A-M. Valente-Feliciano
JLab, Newport News, Virginia, USA

Funding: NSF Grants PHY-1734075 and PHY-1416051, and DOE Awards DE-SC0010081 and DE-SC0019399
Over the past few decades, bulk niobium (Nb) has been the material of choice for superconducting radio frequen-cy (SRF) cavities used in particle accelerators to achieve higher accelerating gradients and lower RF losses. Multi-layer (SIS) structures consisting of alternating thin layers of superconductor(S) and insulator(I) deposited on a bulk Nb have been proposed to enhance the peak surface magnetic field and sustain a higher accelerating gradient. In this study, multilayers based NbTiN and AlN deposited on bulk Nb are used to test the proposed enhancement using the DC magnetic Hall probe technique. The tech-nique detects a penetrating magnetic field through the multilayer sample as it is placed under an external mag-netic field produced by a magnetic coil. This work re-ports the characterization and measurements of the mag-netic field of full flux penetration through single layers of NbTiN and bilayers of NbTiN/AlN on bulk Nb.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE19

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Received ※ 24 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 08 September 2022 — Issue date ※ 15 September 2022

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THPOGE22

Medium Temperature Treatments of Superconducting Radio Frequency Cavities at DESY

niobium, SRF, factory, accelerating-gradient

840

L. Steder, C. Bate, H. Remde, D. Reschke, J. Schaffran, L. Trelle, H. Weise, M. Wiencek
DESY, Hamburg, Germany
M. Wenskat
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

Over the last years several different approaches to increase the performance of superconducting radio frequency (SRF) cavities by heat treatments have been developed and tested. At DESY, the R&D aims for cavities with enlarged quality factors while maintaining high accelerating gradients, since an envisaged upgrade of the European XFEL requires both. For this purpose, medium temperature (mid-T) treatments around 300 °C seem to be very promising. Lately, the furnace infrastructure at DESY was refurbished and now a niobium-retort furnace capable of carrying 1.3 GHz nine-cell cavities can be used for R&D studies. Vertical test results of single-cell cavities treated in this furnace at medium temperatures are presented and compared to four cavities treated similarly in a furnace at the company Zanon Research & Innovation Srl (Zanon). All mentioned cavities show enlarged quality factors but at the same time reduced gradients compared to their reference measurements before the mid-T treatment. The DESY treatments were accompanied by small niobium samples for surface analyses, which are also presented. Furthermore, the influence of post-treatment high pressure water rinsings is studied.

Slides THPOGE22 [1.277 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE22

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Received ※ 19 August 2022 — Revised ※ 23 August 2022 — Accepted ※ 27 August 2022 — Issue date ※ 15 September 2022

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THPOGE23

Vertical Electro-Polishing of 704 MHz Resonators Using Ninja Cathode: Gradients Over 40 MV/m Achieved on ESS Single-Cell Cavity

cathode, niobium, SRF, linac

844

F. Éozénou, M. Baudrier, E. Cenni, E. Fayette, L. Maurice, C. Servouin
CEA-DRF-IRFU, France
H. Hayano, H. Ito, S. Kato, T. Kubo, H. Monjushiro, T. Saeki
KEK, Ibaraki, Japan
Y.I. Ida, K. Nii, T.Y. Yamaguchi
MGH, Hyogo-ken, Japan
G. Jullien
CEA-IRFU, Gif-sur-Yvette, France

CEA, KEK and Marui Galvanizing Company have been collaborating to apply the Vertical Electropolishing (VEP) process of elliptical SRF cavities to a 704MHz single-cell ESS-type cavity, using a rotating so called and patented "Ninja" cathode. First presented results* were promising with a gradient of 27MV/m achieved, without any heat treatment applied. The performance has been pushed further since. The cavity has undergone a heat treatment at 650°C during 10h, followed by a final VEP sequence and a baking at 120°C during 48h hours. The achieved gradient at 2K was 44MV/m (power limitation), and the quality factor Q₀ exceeding 5·10¹⁰ up to 10 MV/m. The superiority of VEP compared to standard "BCP" chemical treatment is demonstrated and we intend now to scale the process to 5-Cell β=0.86 ESS cavity. We also intend to push further the performance by applying "2-step baking" (75°C and 120°C) proposed by FNAL, which was successfully applied at CEA Saclay on 1300MHz single-cell resonators with gradients above 50MV/m achieved after VEP bulk treatment.
* TUPCAV001, SRF 2021

Slides THPOGE23 [0.868 MB]

Poster THPOGE23 [0.918 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE23

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Received ※ 24 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 09 September 2022 — Issue date ※ 16 September 2022

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THPORI15

Operation of the CLARA Linear Accelerator with 2.5 Cell 10 Hz Photocathode Gun with Interchangeable Photocathodes

cathode, gun, operation, MMI

854

B.L. Militsyn, D. Angal-Kalinin, A.R. Bainbridge, L.S. Cowie, A.J. Gilfellon, F. Jackson, N.Y. Joshi, K.J. Middleman, K.T. Morrow, T.C.Q. Noakes, M.D. Roper, R. Valizadeh, D.A. Walsh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
R.J. Cash, B.D. Fell, T.J. Jones, A.J. Vick
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

During commissioning and operation run in 2021-2022 the photoinjector of the CLARA-VELA facility a 2.5 cell cavity S-band photocathode gun originally developed for the APEX experiment was used. The copper back wall of the cavity also served as the gun photocathode. In order to reduce significant time required for replacement and/or reactivation of the photocathode and improve the flexibility of the injector the gun has been upgraded for operation with DESY/INFN style interchangeable photocathodes. This upgrade included a new design of the cavity back wall to accommodate the photocathode socket and equipping the gun with a load-lock system. Modification of the gun also required replacement of the bucking coil, which zeros field in the photocathode emission plane. After the upgrade, the gun was commissioned and then operated with a hybrid Cu/Mo photocathode during the last two years. During winter-spring 2022 experimental run the gun steadily operated with a cathode field of 60 MV/m, limited by the RF power available and with an off-centre diamond turned photocathode which delivered stable bunches with a charge of 100 pC.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPORI15

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Received ※ 24 August 2022 — Revised ※ 08 September 2022 — Accepted ※ 12 September 2022 — Issue date ※ 15 October 2022

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THPORI16

Machine Learning for RF Breakdown Detection at CLARA

network, detector, gun, operation

858

A.E. Pollard, D.J. Dunning, A.J. Gilfellon
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Maximising the accelerating gradient of RF structures is fundamental to improving accelerator facility performance and cost-effectiveness. Structures must be subjected to a conditioning process before operational use, in which the gradient is gradually increased up to the operating value. A limiting effect during this process is breakdown or vacuum arcing, which can cause damage that limits the ultimate operating gradient. Techniques to efficiently condition the cavities while minimising the number of breakdowns are therefore important. In this paper, machine learning techniques are applied to detect breakdown events in RF pulse traces by approaching the problem as anomaly detection, using a variational autoencoder. This process detects deviations from normal operation and classifies them with near perfect accuracy. Offline data from various sources has been used to develop the techniques, which we aim to test at the CLARA facility at Daresbury Laboratory. Deployment of the machine learning system on the high repetition rate gun upgrade at CLARA has begun.

Poster THPORI16 [2.099 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPORI16

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Received ※ 22 August 2022 — Revised ※ 30 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 15 October 2022

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FR1AA03

Status and Challenges at TRIUMF ISAC Facility

ISAC, linac, operation, LLRF

866

Z.Y. Yao, Z.T. Ang, T. Au, K. Fong, X.L. Fu, J.J. Keir, P. Kolb, D. Lang, R.E. Laxdal, R. Leewe, Y. Ma, B. Matheson, R.S. Sekhon, B.S. Waraich, Q. Zheng, V. Zvyagintsev
TRIUMF, Vancouver, Canada

The ISAC facility uses the ISOL technique to produce radioactive ions for experiments. The post-accelerator consists of a room temperature linac (ISAC-I) and a su-perconducting linac (ISAC-II). After more than two dec-ades of beam delivery in ISAC, the RF systems have met various challenges regarding increased operation require-ments, system stability issues and performance improve-ments. This paper discusses the detailed challenges in recent years in both ISAC-I and ISAC-II. The upgrade plan or mitigation solution to address each challenge is reported respectively. A hint of the long-term vision at ISAC is also briefly described at the end of the paper.

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Slides FR1AA03 [6.986 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-FR1AA03

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Received ※ 13 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022

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FR1AA06

Fully Automated Tuning and Recover of a High Power SCL

linac, controls, experiment, superconducting-cavity

884

A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA
C.C. Peters
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.
Techniques have been developed for fast (less than one hour), fully automated tune-up a high power proton SCL, as well as fully automated recovery from a cavity failure with no human intervention. These methods have been developed and demonstrated at the SNS SCL but are applicable to hadron SCL operation in general and will be especially relevant to future ADS applications

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Slides FR1AA06 [1.112 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-FR1AA06

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Received ※ 23 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 04 September 2022

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