LINAC2022 - List of Keywords (multipactoring)

Paper	Title	Other Keywords	Page
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)	cavity, 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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOPA05	RFQ Performance During RF Conditioning and Beam Commissioning at ESS	rfq, cavity, beam-loading, 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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOPA15	Multipactor Studies: Simulations and Measurements on the RF Coaxial Resonator Test Bench	electron, simulation, cavity, 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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOPA16	Complete Study of the Multipactor Phenomenon for the MYRRHA 80 kW CW RF Couplers	electron, simulation, cavity, 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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOPA18	Test and Commissioning of the HELIAC Power Coupler	cavity, operation, cryomodule, 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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOPA25	Design, Manufacturing, Assembly, Testing, and Lessons Learned of the Prototype 650 MHz Couplers	vacuum, SRF, cryomodule, cavity	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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TUPOPA29	Design Enhancements for the SNS RFQ Coaxial Coupler	rfq, coupling, simulation, operation	469
	G.D. Toby, C.N. Barbier, Y.W. Kang, S.W. Lee, J.S. Moss ORNL, Oak Ridge, Tennessee, USA A.H. Narayan ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. This research was supported by the DOE Office of Science, Basic Energy Science. The H⁻ ion linear accelerator at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory operates with reliability that routinely surpasses 90% during scheduled beam operation. With the ambitious goal of eventually achieving at least 95% availability, several upgrade and improvement projects are ongoing. One such project is the modification of the coaxial couplers that transfer radio frequency (RF) power to the accelerator’s Radio Frequency Quadrupole (RFQ). The proposed modification utilizes stub sections and capacitive coupling to construct a physically separable assembly with DC isolation. With a separated coupler assembly, the section that includes the magnetic coupling loop can be permanently mounted to the RFQ which would eliminate the need to re-adjust the couplers after maintenance activities, upgrades, and repairs. Additionally, the modified design would provide increased multipaction suppression with DC biasing and potentially lower thermal gradients across the device. This paper presents the design and simulation results of the project.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA29
About •	Received ※ 23 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 01 September 2022
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TUPOGE04	An Approach for Component-Level Analysis of Cryogenic Process in Superconducting LINAC Cryomodules	cryomodule, cavity, cryogenics, linac	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
About •	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	cavity, cryomodule, 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
About •	Received ※ 14 August 2022 — Revised ※ 23 August 2022 — Accepted ※ 12 September 2022 — Issue date ※ 15 September 2022
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TH2AA02	RF System Performance in the SwissFEL Linac	klystron, linac, operation, FEL	679
	C.D. Beard, J. Alex, H.-H. Braun, P. Craievich, Z. Geng, N. Hiller, R. Kalt, C. Kittel, T. Lippuner, T.G. Lucas, M. Pedrozzi, E. Prat, S. Reiche, T. Schietinger, W.T. Tron, D. Voulot, R. Zennaro PSI, Villigen PSI, Switzerland
	The Hard X-ray FEL machine SwissFEL at the Paul Scherrer Institut in Switzerland is commissioned and transiting to user operation smoothly. FEL operation requires stringent requirements for the beam stability at the linac output, such as the electron bunch arrival time, peak current and beam energy. Among other things, a highly stable RF system is required to guarantee the beam stability. RF performance often dominates the overall performance and availability of FELs, and for this reason the SwissFEL RF system has been designed based on the state-of-the-art technologies that have enabled excellent RF stability, resulting in an arrival time jitter of ~10 fs rms and relative beam energy stability of 10^-4 rms. This paper aims to provide an understanding of the peak performance of the RF systems and to highlight possible limitation currently faced, focusing on the S-, C- and X-Band systems.

	please see instructions how to view/control embeded videos
	Slides TH2AA02 [4.813 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TH2AA02
About •	Received ※ 20 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 02 September 2022
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THPOGE01	Study on the Multipactor Barriers of the SARAF-Phase 2 Low-Beta and High-Beta Superconducting Cavities	cavity, 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
About •	Received ※ 27 July 2022 — Revised ※ 23 August 2022 — Accepted ※ 07 September 2022 — Issue date ※ 15 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	cavity, electron, accelerating-gradient, 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
About •	Received ※ 22 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 14 October 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

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)

cavity, 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

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOPA05

RFQ Performance During RF Conditioning and Beam Commissioning at ESS

rfq, cavity, beam-loading, 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

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOPA15

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

electron, simulation, cavity, 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

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOPA16

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

electron, simulation, cavity, 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

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOPA18

Test and Commissioning of the HELIAC Power Coupler

cavity, operation, cryomodule, 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

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOPA25

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

vacuum, SRF, cryomodule, cavity

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

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOPA29

Design Enhancements for the SNS RFQ Coaxial Coupler

rfq, coupling, simulation, operation

469

G.D. Toby, C.N. Barbier, Y.W. Kang, S.W. Lee, J.S. Moss
ORNL, Oak Ridge, Tennessee, USA
A.H. Narayan
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. This research was supported by the DOE Office of Science, Basic Energy Science.
The H⁻ ion linear accelerator at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory operates with reliability that routinely surpasses 90% during scheduled beam operation. With the ambitious goal of eventually achieving at least 95% availability, several upgrade and improvement projects are ongoing. One such project is the modification of the coaxial couplers that transfer radio frequency (RF) power to the accelerator’s Radio Frequency Quadrupole (RFQ). The proposed modification utilizes stub sections and capacitive coupling to construct a physically separable assembly with DC isolation. With a separated coupler assembly, the section that includes the magnetic coupling loop can be permanently mounted to the RFQ which would eliminate the need to re-adjust the couplers after maintenance activities, upgrades, and repairs. Additionally, the modified design would provide increased multipaction suppression with DC biasing and potentially lower thermal gradients across the device. This paper presents the design and simulation results of the project.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA29

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Received ※ 23 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 01 September 2022

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TUPOGE04

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

cryomodule, cavity, cryogenics, linac

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

cavity, cryomodule, 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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TH2AA02

RF System Performance in the SwissFEL Linac

klystron, linac, operation, FEL

679

C.D. Beard, J. Alex, H.-H. Braun, P. Craievich, Z. Geng, N. Hiller, R. Kalt, C. Kittel, T. Lippuner, T.G. Lucas, M. Pedrozzi, E. Prat, S. Reiche, T. Schietinger, W.T. Tron, D. Voulot, R. Zennaro
PSI, Villigen PSI, Switzerland

The Hard X-ray FEL machine SwissFEL at the Paul Scherrer Institut in Switzerland is commissioned and transiting to user operation smoothly. FEL operation requires stringent requirements for the beam stability at the linac output, such as the electron bunch arrival time, peak current and beam energy. Among other things, a highly stable RF system is required to guarantee the beam stability. RF performance often dominates the overall performance and availability of FELs, and for this reason the SwissFEL RF system has been designed based on the state-of-the-art technologies that have enabled excellent RF stability, resulting in an arrival time jitter of ~10 fs rms and relative beam energy stability of 10^-4 rms. This paper aims to provide an understanding of the peak performance of the RF systems and to highlight possible limitation currently faced, focusing on the S-, C- and X-Band systems.

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Slides TH2AA02 [4.813 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TH2AA02

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Received ※ 20 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 02 September 2022

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THPOGE01

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

cavity, 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

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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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THPOGE03

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

cavity, electron, accelerating-gradient, 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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