LINAC2022 - Table of Session: MOPORI (Poster Session)

Paper	Title	Page
MOPORI01	A Multi-Camera System for Tomographic Beam Diagnostics	215
	A. Ateş, G. Blank, H. Hähnel, U. Ratzinger IAP, Frankfurt am Main, Germany
	A prototype of a beam-induced residual gas fluorescence monitor (BIF) has been developed and successfully tested at the Institute of Applied Physics (IAP) of the Goethe University Frankfurt. This BIF is based on ten single-board cameras inserted into the vacuum and directed onto the beam axis. The overall goal is to study the beam with tomography algorithms at a low energy beam transport section. Recently, we tested the detector with a 60keV, 15mA proton beam at 20Hz and 1ms puls length. In this paper we present the ongoing investigations on image processing and application of the algebraic reconstruction technique (ART).
	Poster MOPORI01 [1.826 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI01
About •	Received ※ 20 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 01 September 2022
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MOPORI02	Implementation of an Advanced MicroTCA.4-based Digitizer for Monitoring Comb-Like Beam at the J-PARC Linac	219
	E. Cicek, K. Futatsukawa, T. Miyao, S. Mizobata KEK, Ibaraki, Japan N. Hayashi, A. Miura, K. Moriya JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The Japan Proton Accelerator Research Complex (J-PARC) linac beam pulse, generated by a beam chopper system placed at the MEBT, comprises a series of intermediate pulses with a comb-like structure synchronized with the radio-frequency of the rapid cycling synchrotron (RCS). The sequentially measuring and monitoring the comb-like beam pulse ensures the beam stability with less beam loss at the current operation and higher beam intensity scenarios at the J-PARC. However, signal processing as a function of the pulse structure is challenging using a general-purpose digitizer, and monitoring the entire macro pulse during the beam operation is unavailable. To this end, an advanced beam monitor digitizer complying with the MicroTCA.4 (MicroTelecommunications Computing Architecture.4) standard, including digital signal processing functions, has been developed. This paper reports the implementation, performance evaluation, and the first results of this unique beam monitor digitizer.
	Poster MOPORI02 [7.902 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI02
About •	Received ※ 13 August 2022 — Accepted ※ 22 August 2022 — Issue date ※ 01 September 2022
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MOPORI03	Development of Quantum Gas Jet Beam Profile Monitor for Sub-mm Beams	223
	N. Kumar, O. Stringer, C.P. Welsch, J. Wolfenden, H.D. Zhang The University of Liverpool, Liverpool, United Kingdom N. Kumar, C.P. Welsch, J. Wolfenden, H.D. Zhang Cockcroft Institute, Warrington, Cheshire, United Kingdom I. Maltusch FH Aachen, Jülich, Germany
	Funding: This work is supported by the STFC grants ST/W000687/1 and ST/W002159/1, InnovateUK Germinator 10004615, HL-LHC-UK project funded by STFC and CERN and the STFC Cockcroft core grant No. ST/G008248/1. The development work of a high-resolution quantum gas jet beam profile monitor for highly energetic sub-mm particle beams is in progress at the Cockcroft Institute (CI), UK. This device is designed on the principle of detecting the secondary ions from the ionisation induced in the interaction between the quantum gas jet and charged particle beams. This monitor aims to generate an intense gas jet with a diameter of less than 100 µm, which can ultimately lead to superior position resolution and high signal intensity resulting from a strongly focused quantum gas jet. This is done by exploiting the quantum wave feature of the neutral gas atoms to generate an interference pattern with a single maximum acting as an ultra-thin gas jet using an ’atom sieve’ which is similar to the light focusing with a Fresnel zone plate. This device will be minimally interceptive and will work analogously to a mechanical wire scanner. This contribution gives a general overview of the design, working principle of the monitor and experimental results obtained from the electron beam profile measurements carried out at the Cockcroft Institute.
	Poster MOPORI03 [1.581 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI03
About •	Received ※ 13 August 2022 — Revised ※ 16 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 01 September 2022
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MOPORI04	A Gas Jet Beam Halo Monitor for LINACs	227
	O. Stringer, N. Kumar, C.P. Welsch, H.D. Zhang The University of Liverpool, Liverpool, United Kingdom N. Kumar, O. Stringer, C.P. Welsch, H.D. Zhang Cockcroft Institute, Warrington, Cheshire, United Kingdom
	The gas jet beam profile monitor is a non-invasive beam monitor that is currently being commissioned at the Cockcroft Institute. It utilises a supersonic gas curtain which traverses the beam perpendicular to its propagation and measures beam-induced ionisation interactions of the gas. A 2D transverse beam profile image is created by orientating the gas jet 45 degrees to obtain both X and Y distributions of the beam. This paper builds upon previously used single-slit skimmers and improves their ability to form the gas jet into a desired distribution for imaging beam halo. A skimmer device removes off-momentum gas particles and forms the jet into a dense thin curtain, suitable for transverse imaging of the beam. The use of a novel double-slit skimmer is shown to provide a mask-like void of gas over the beam core, increasing the relative intensity of the halo interactions for measurement. Such a non-invasive monitor would be beneficial to linacs by providing real time beam characteristic measurements without affecting the beam. More specifically, beam halo behaviour is a key characteristic associated with beam losses within linacs.
	Poster MOPORI04 [1.066 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI04
About •	Received ※ 24 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 13 October 2022
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MOPORI05	Application of Virtual Diagnostics in the FEBE Clara User Area	231
	J. Wolfenden, C. Swain, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom D.J. Dunning, J.K. Jones, T.H. Pacey, A.E. Pollard STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom C. Swain, C.P. Welsch, J. Wolfenden Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: This work is supported by the AWAKE-UK phase II project funded by STFC and the STFC Cockcroft core grant No. ST/G008248/1. Successful user experiments at particle beam facilities are dependent upon the awareness of beam characteristics at the interaction point. Often, properties are measured beforehand for fixed operation modes; users then rely on the long-term stability of the beam. Otherwise, diagnostics must be integrated into a user experiment, costing resources and limiting space in the user area. This contribution proposes the application of machine learning to develop a suite of virtual diagnostic systems. Virtual diagnostics take data at easy to access locations, and infer beam properties at locations where a measurement has not been taken, and often cannot be taken. Here the focus is the user area at the planned Full Energy Beam Exploitation (FEBE) upgrade to the CLARA facility (UK). Presented is a simulation-based proof-of-concept for a variety of virtual diagnostics. Transverse and longitudinal properties are measured upstream of the user area, coupled with the beam optics parameters leading to the user area, and input into a neural network, to predict the same parameters within the user area. Potential instrumentation for FEBE CLARA virtual diagnostics will also be discussed.
	Poster MOPORI05 [0.613 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI05
About •	Received ※ 17 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 01 September 2022
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MOPORI06	Improvements on the Modified Nomarski Interferometer for Measurements of Supersonic Gas Jet Density Profiles	235
	C. Swain, Ö. Apsimon, A. Salehilashkajani, C.P. Welsch, J. Wolfenden, H.D. Zhang Cockcroft Institute, Warrington, Cheshire, United Kingdom Ö. Apsimon, A. Salehilashkajani, C. Swain, C.P. Welsch, J. Wolfenden, H.D. Zhang The University of Liverpool, Liverpool, United Kingdom
	Funding: This work is supported by the AWAKE-UK phase II project funded by STFC, the STFC Cockcroft core grant No. ST/G008248/1 and the HL-LHC-UK phase II project funded by STFC under Grant Ref: ST/T001925/1. For supersonic gas jet based beam profile monitors such as that developed for the High Luminosity Large Hadron Collider (HL-LHC) upgrade, density profile is a key characteristic. Due to this, non-invasive diagnostics to study the jet’s behaviour have been designed. A Nomarski interferometer was constructed to image jets 30 um to 1 mm in diameter and study changes in their density. A microscope lens has been integrated into the original interferometer system to capture phase changes on a much smaller scale than previous experiments have achieved. This contribution presents the optimisation and results gained from this interferometer.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI06
About •	Received ※ 14 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022
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MOPORI08	Beam Mapping Linearity Improvement in Multi-Dimensional Bunch Shape Monitor	239
	S.V. Kutsaev, R.B. Agustsson, A.C. Araujo Martinezpresenter, 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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MOPORI09	Linear Accelerator for Demonstration of X-Ray Radiotherapy with Flash Effect	243
MOOPA01	use link to see paper's listing under its alternate paper code
	S.V. Kutsaev, R.B. Agustsson, S. Boucher, K. Kaneta, A.Yu. Smirnov, V.S. Yu RadiaBeam, Santa Monica, California, USA A.R. Li, K. Sheng UCLA, Los Angeles, California, USA
	Funding: This project is funded by NIH, award number NIH R01CA255432. Emerging evidence indicates that the therapeutic window of radiotherapy can be significantly increased using ultra-high dose rate dose delivery (FLASH), by which the normal tissue injury is reduced without compromising tumor cell killing. The dose rate required for FLASH is 40 Gy/s or higher, 2-3 orders of magnitude greater than conventional radiotherapy. Among the major technical challenges in achieving the FLASH dose rate with X-rays is a linear accelerator that is capable of producing such a high dose rate. We will discuss the design of a high dose rate 18 MeV linac capable of delivering 100 Gy/s of collimated X-rays at 20 cm. This linac is being developed by a RadiaBeam/UCLA collaboration for a preclinical system as a demonstration of the FLASH effect in small animals.
	Slides MOPORI09 [0.954 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI09
About •	Received ※ 19 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 02 September 2022
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MOPORI10	First Studies of 5D Phase-Space Tomography of Electron Beams at ARES	247
SUPCJO05	use link to see paper's listing under its alternate paper code
MOOPA09	use link to see paper's listing under its alternate paper code
	S. Jaster-Merz, R.W. Aßmann, R. Brinkmann, F. Burkart, T. Vinatier DESY, Hamburg, Germany R.W. Aßmann LNF-INFN, Frascati, Italy
	A new beam diagnostics method to reconstruct the full 5-dimensional phase space (x, x’, y, y’, t) of bunches has recently been proposed. This method combines a quadrupole-based transverse phase-space tomography with the variable streaking angle of a polarizable X-band transverse deflecting structure (PolariX TDS). Two of these novel structures have recently been installed at the ARES beamline at DESY, which is a linear accelerator dedicated to accelerator research and development, including advanced diagnostics methods and novel accelerating techniques. In this paper, realistic simulation studies in preparation for planned experimental measurements are presented using the beamline setup at ARES. The reconstruction quality of the method for three beam distributions is studied and discussed, and it is shown how this method will allow the visualization of detailed features in the phase-space distribution.
	Slides MOPORI10 [0.808 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI10
About •	Received ※ 22 August 2022 — Revised ※ 27 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 09 September 2022
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MOPORI11	Seismic Analysis for Safety Requirements of SPIRAL2 Accelerator	252
	C. Barthe-Dejean, F. Lutton, M. Michel GANIL, Caen, France
	The SPIRAL2 Accelerator at GANIL is a superconducting ion continuous wave LINAC with two associated experimental areas. Mechanical engineers have been highly involved in the design of SPIRAL2 equipments since the beginning of the project in 2004. During the development phase, Computer Aided Design and calculation codes have been used throughout the complete process : from the ion sources, the LINAC, the beam transport lines and the experimental halls equipped with detectors. SPIRAL2 has to meet different safety requirements, among which seismic hazard. This involves justifying that the integrity of the radiologic containment barrier is always maintained in case of earthquake. This paper reports the improvement in design and calculation methods performed by GANIL engineers to meet the seismic safety requirements, specificly the non-missility feature of the equpiment. The modal-spectral simulations, used to demonstrate the mechanical strength of equipments in case of earthquakes, was an important part of this design activity in the past 10 years New methods have been used to calculate welds, fasteners and the ground anchor of the structural supports of the heaviest equipments. C. Barthe-Dejean, F. Lutton, « Guide methodologique pour Calculs de Tenue aux Séismes des équipements mécaniques », Note STP-535-A
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI11
About •	Received ※ 14 August 2022 — Revised ※ 19 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 02 September 2022
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MOPORI12	Development of Commercial RFQ Toward CW Applications	255
MOOPA08	use link to see paper's listing under its alternate paper code
	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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MOPORI13	On the UNILAC Pulsed Gas Stripper at GSI	258
	P. Gerhard, M.T. Maier GSI, Darmstadt, Germany
	The UNILAC will serve as injector linac for heavy ion beams for the future FAIR, with the commissioning being anticipated in 2025. One of the crucial steps in the course of acceleration along the UNILAC is the stripping of the ions by a gas stripper in front of the main linac. Its efficiency is decisive in reaching the intensities required and may be increased by more than 50% by introducing hydrogen as stripping target, instead of the nitrogen used so far. This requires the stripper to be operated in a pulsed mode, since otherwise the pumping speed is not sufficient to maintain suitable vacuum conditions. The proof of principle was demonstrated in 2016. A dedicated project aims for a setup suitable for routine operation. Main issues are safety, reliability and automated operation. We report on the development done since 2016 and give an overview of the realisation coming within the next few years. Results from systematic measurements on the properties of the valves and their impact on the properties of the stripping target are presented. P. Scharrer et al., Developments on the 1.4 MeV/u Pulsed Gas Stripper Cell, in Proc. LINAC2016, East Lansing, MI, USA, Sep. 2016. https://doi.org/10.18429/JACoW-LINAC2016-TUOP03
	Poster MOPORI13 [1.908 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI13
About •	Received ※ 05 August 2022 — Accepted ※ 14 August 2022 — Issue date ※ 02 September 2022
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MOPORI15	Update of Adjustable PMQ Lens	262
	Y. Iwashita Kyoto University, Research Reactor Institute, Osaka, Japan Y. Fuwa JAEA/J-PARC, Tokai-mura, Japan T. Hosokai ISIR, Osaka, Japan D. Oumbarek Espinos Osaka University, Graduate School of Engineering, Osaka, Japan
	Gluckstern’s adjustable permanent magnet quadrupole (PMQ) lens based on five rings is revisited to achieve a compact focusing system for laser-accelerated beams. The first prototype was fabricated for bore diameter of 50 mm. The integrated gradient was up to 6.8 T. A new PMQ with a bore diameter of 25 mm is under fabrication based on the same geometry. While the first prototype unit was developed for the final focus magnet of the ILC, the sec-ond unit is the first doublet element for laser-accelerated electron beam focusing to be combined with this first unit. The current status of the development is reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI15
About •	Received ※ 01 September 2022 — Revised ※ 03 September 2022 — Accepted ※ 05 September 2022 — Issue date ※ 15 September 2022
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MOPORI17	The ESS Fast Beam Interlock System: First Experience of Operating With Proton Beam	265
	S. Gabourin, M. Carroll, S. Kövecses de Carvalho, A. Nordt, S. Pavinatopresenter, K. Rosquist ESS, Lund, Sweden
	The European Spallation Source (ESS), Sweden, currently in its early operation phase, aims to be the most powerful neutron source in the world. Proton beam pulses are accelerated and sent to a rotating tungsten target, where neutrons are generated via the spallation effect. The damage potential of the ESS proton beam is high and melting of copper or steel can happen within less than 5 microseconds. Therefore, highly reliable and fast machine protection (MP) systems have been designed and deployed. The core system of ESS Machine Protection is the Fast Beam Interlock System (FBIS), based on FPGA technology. FBIS collects data from all relevant accelerator and target systems through 300 direct inputs and decides whether beam operation can start or must stop. The architecture is based on two main building blocks: Decision Logic Node (DLN), executing the protection logic and realizing interfaces to Higher-Level Safety, Timing System and EPICS Control System. The second block, the Signal Condition Unit (SCU), implements the interface between FBIS inputs/outputs and DLNs. This paper gives an overview on FBIS and a summary on its performance during beam commissioning phases since 2021.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI17
About •	Received ※ 19 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 03 September 2022
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MOPORI18	Overview of STFC Daresbury Laboratory Vacuum Operations for the Testing of ESS High Beta Cavities.	268
	S. Wilde, K.J. Middleman, M.D. Pendleton, J.O.W. Poyntonpresenter 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	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	275
SUPCRI07	use link to see paper's listing under its alternate paper code
	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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MOPORI23	High-Power Testing Results of X-Band RF-Window and 45 Degrees Spiral Load	279
	M. Boronat, H. Bursali, N. Catalán Lasheras, A. Grudiev, G. McMonagle, I. Syratchev CERN, Meyrin, Switzerland
	The X-Band test facilities at CERN have been running for some years now qualifying CLIC structure prototypes but also developing and testing high power general-purpose X-Band components, used in a wide range of applications. Driven by operational needs, several components have been redesigned and tested aiming to optimize the reliability and the compactness of the full system and therefore enhancing the accessibility of this technology inside and outside CERN. To this extent, a new high-power RF-window has been designed and tested aiming to avoid unnecessary venting of high-power sections already conditioned, easing the interventions, and protecting the klystrons. A new spiral load prototype has also been designed, built, and tested, optimizing the compactness, and improving the fabrication process. In these pages, the design and manufacturing for each component will be shortly described, along with the last results on the high-power testing.
	Poster MOPORI23 [2.275 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI23
About •	Received ※ 24 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 31 August 2022
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MOPORI24	Monte Carlo Model of High-Voltage Conditioning and Operation	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	287
SUPCRI02	use link to see paper's listing under its alternate paper code
	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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Paper

Title

Page

A Multi-Camera System for Tomographic Beam Diagnostics

215

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

A prototype of a beam-induced residual gas fluorescence monitor (BIF) has been developed and successfully tested at the Institute of Applied Physics (IAP) of the Goethe University Frankfurt. This BIF is based on ten single-board cameras inserted into the vacuum and directed onto the beam axis. The overall goal is to study the beam with tomography algorithms at a low energy beam transport section. Recently, we tested the detector with a 60keV, 15mA proton beam at 20Hz and 1ms puls length. In this paper we present the ongoing investigations on image processing and application of the algebraic reconstruction technique (ART).

Poster MOPORI01 [1.826 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI01

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Received ※ 20 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 01 September 2022

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MOPORI02

Implementation of an Advanced MicroTCA.4-based Digitizer for Monitoring Comb-Like Beam at the J-PARC Linac

219

E. Cicek, K. Futatsukawa, T. Miyao, S. Mizobata
KEK, Ibaraki, Japan
N. Hayashi, A. Miura, K. Moriya
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The Japan Proton Accelerator Research Complex (J-PARC) linac beam pulse, generated by a beam chopper system placed at the MEBT, comprises a series of intermediate pulses with a comb-like structure synchronized with the radio-frequency of the rapid cycling synchrotron (RCS). The sequentially measuring and monitoring the comb-like beam pulse ensures the beam stability with less beam loss at the current operation and higher beam intensity scenarios at the J-PARC. However, signal processing as a function of the pulse structure is challenging using a general-purpose digitizer, and monitoring the entire macro pulse during the beam operation is unavailable. To this end, an advanced beam monitor digitizer complying with the MicroTCA.4 (MicroTelecommunications Computing Architecture.4) standard, including digital signal processing functions, has been developed. This paper reports the implementation, performance evaluation, and the first results of this unique beam monitor digitizer.

Poster MOPORI02 [7.902 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI02

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Received ※ 13 August 2022 — Accepted ※ 22 August 2022 — Issue date ※ 01 September 2022

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MOPORI03

Development of Quantum Gas Jet Beam Profile Monitor for Sub-mm Beams

223

N. Kumar, O. Stringer, C.P. Welsch, J. Wolfenden, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom
N. Kumar, C.P. Welsch, J. Wolfenden, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
I. Maltusch
FH Aachen, Jülich, Germany

Funding: This work is supported by the STFC grants ST/W000687/1 and ST/W002159/1, InnovateUK Germinator 10004615, HL-LHC-UK project funded by STFC and CERN and the STFC Cockcroft core grant No. ST/G008248/1.
The development work of a high-resolution quantum gas jet beam profile monitor for highly energetic sub-mm particle beams is in progress at the Cockcroft Institute (CI), UK. This device is designed on the principle of detecting the secondary ions from the ionisation induced in the interaction between the quantum gas jet and charged particle beams. This monitor aims to generate an intense gas jet with a diameter of less than 100 µm, which can ultimately lead to superior position resolution and high signal intensity resulting from a strongly focused quantum gas jet. This is done by exploiting the quantum wave feature of the neutral gas atoms to generate an interference pattern with a single maximum acting as an ultra-thin gas jet using an ’atom sieve’ which is similar to the light focusing with a Fresnel zone plate. This device will be minimally interceptive and will work analogously to a mechanical wire scanner. This contribution gives a general overview of the design, working principle of the monitor and experimental results obtained from the electron beam profile measurements carried out at the Cockcroft Institute.

Poster MOPORI03 [1.581 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI03

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Received ※ 13 August 2022 — Revised ※ 16 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 01 September 2022

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MOPORI04

A Gas Jet Beam Halo Monitor for LINACs

227

O. Stringer, N. Kumar, C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom
N. Kumar, O. Stringer, C.P. Welsch, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom

The gas jet beam profile monitor is a non-invasive beam monitor that is currently being commissioned at the Cockcroft Institute. It utilises a supersonic gas curtain which traverses the beam perpendicular to its propagation and measures beam-induced ionisation interactions of the gas. A 2D transverse beam profile image is created by orientating the gas jet 45 degrees to obtain both X and Y distributions of the beam. This paper builds upon previously used single-slit skimmers and improves their ability to form the gas jet into a desired distribution for imaging beam halo. A skimmer device removes off-momentum gas particles and forms the jet into a dense thin curtain, suitable for transverse imaging of the beam. The use of a novel double-slit skimmer is shown to provide a mask-like void of gas over the beam core, increasing the relative intensity of the halo interactions for measurement. Such a non-invasive monitor would be beneficial to linacs by providing real time beam characteristic measurements without affecting the beam. More specifically, beam halo behaviour is a key characteristic associated with beam losses within linacs.

Poster MOPORI04 [1.066 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI04

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Received ※ 24 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 13 October 2022

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MOPORI05

Application of Virtual Diagnostics in the FEBE Clara User Area

231

J. Wolfenden, C. Swain, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
D.J. Dunning, J.K. Jones, T.H. Pacey, A.E. Pollard
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
C. Swain, C.P. Welsch, J. Wolfenden
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This work is supported by the AWAKE-UK phase II project funded by STFC and the STFC Cockcroft core grant No. ST/G008248/1.
Successful user experiments at particle beam facilities are dependent upon the awareness of beam characteristics at the interaction point. Often, properties are measured beforehand for fixed operation modes; users then rely on the long-term stability of the beam. Otherwise, diagnostics must be integrated into a user experiment, costing resources and limiting space in the user area. This contribution proposes the application of machine learning to develop a suite of virtual diagnostic systems. Virtual diagnostics take data at easy to access locations, and infer beam properties at locations where a measurement has not been taken, and often cannot be taken. Here the focus is the user area at the planned Full Energy Beam Exploitation (FEBE) upgrade to the CLARA facility (UK). Presented is a simulation-based proof-of-concept for a variety of virtual diagnostics. Transverse and longitudinal properties are measured upstream of the user area, coupled with the beam optics parameters leading to the user area, and input into a neural network, to predict the same parameters within the user area. Potential instrumentation for FEBE CLARA virtual diagnostics will also be discussed.

Poster MOPORI05 [0.613 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI05

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Received ※ 17 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 01 September 2022

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MOPORI06

Improvements on the Modified Nomarski Interferometer for Measurements of Supersonic Gas Jet Density Profiles

235

C. Swain, Ö. Apsimon, A. Salehilashkajani, C.P. Welsch, J. Wolfenden, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
Ö. Apsimon, A. Salehilashkajani, C. Swain, C.P. Welsch, J. Wolfenden, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom

Funding: This work is supported by the AWAKE-UK phase II project funded by STFC, the STFC Cockcroft core grant No. ST/G008248/1 and the HL-LHC-UK phase II project funded by STFC under Grant Ref: ST/T001925/1.
For supersonic gas jet based beam profile monitors such as that developed for the High Luminosity Large Hadron Collider (HL-LHC) upgrade, density profile is a key characteristic. Due to this, non-invasive diagnostics to study the jet’s behaviour have been designed. A Nomarski interferometer was constructed to image jets 30 um to 1 mm in diameter and study changes in their density. A microscope lens has been integrated into the original interferometer system to capture phase changes on a much smaller scale than previous experiments have achieved. This contribution presents the optimisation and results gained from this interferometer.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI06

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Received ※ 14 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022

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MOPORI08

Beam Mapping Linearity Improvement in Multi-Dimensional Bunch Shape Monitor

239

S.V. Kutsaev, R.B. Agustsson, A.C. Araujo Martinezpresenter, 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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MOPORI09

Linear Accelerator for Demonstration of X-Ray Radiotherapy with Flash Effect

243

MOOPA01

use link to see paper's listing under its alternate paper code

S.V. Kutsaev, R.B. Agustsson, S. Boucher, K. Kaneta, A.Yu. Smirnov, V.S. Yu
RadiaBeam, Santa Monica, California, USA
A.R. Li, K. Sheng
UCLA, Los Angeles, California, USA

Funding: This project is funded by NIH, award number NIH R01CA255432.
Emerging evidence indicates that the therapeutic window of radiotherapy can be significantly increased using ultra-high dose rate dose delivery (FLASH), by which the normal tissue injury is reduced without compromising tumor cell killing. The dose rate required for FLASH is 40 Gy/s or higher, 2-3 orders of magnitude greater than conventional radiotherapy. Among the major technical challenges in achieving the FLASH dose rate with X-rays is a linear accelerator that is capable of producing such a high dose rate. We will discuss the design of a high dose rate 18 MeV linac capable of delivering 100 Gy/s of collimated X-rays at 20 cm. This linac is being developed by a RadiaBeam/UCLA collaboration for a preclinical system as a demonstration of the FLASH effect in small animals.

Slides MOPORI09 [0.954 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI09

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Received ※ 19 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 02 September 2022

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MOPORI10

First Studies of 5D Phase-Space Tomography of Electron Beams at ARES

247

SUPCJO05

use link to see paper's listing under its alternate paper code

MOOPA09

use link to see paper's listing under its alternate paper code

S. Jaster-Merz, R.W. Aßmann, R. Brinkmann, F. Burkart, T. Vinatier
DESY, Hamburg, Germany
R.W. Aßmann
LNF-INFN, Frascati, Italy

A new beam diagnostics method to reconstruct the full 5-dimensional phase space (x, x’, y, y’, t) of bunches has recently been proposed. This method combines a quadrupole-based transverse phase-space tomography with the variable streaking angle of a polarizable X-band transverse deflecting structure (PolariX TDS). Two of these novel structures have recently been installed at the ARES beamline at DESY, which is a linear accelerator dedicated to accelerator research and development, including advanced diagnostics methods and novel accelerating techniques. In this paper, realistic simulation studies in preparation for planned experimental measurements are presented using the beamline setup at ARES. The reconstruction quality of the method for three beam distributions is studied and discussed, and it is shown how this method will allow the visualization of detailed features in the phase-space distribution.

Slides MOPORI10 [0.808 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI10

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Received ※ 22 August 2022 — Revised ※ 27 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 09 September 2022

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MOPORI11

Seismic Analysis for Safety Requirements of SPIRAL2 Accelerator

252

C. Barthe-Dejean, F. Lutton, M. Michel
GANIL, Caen, France

The SPIRAL2 Accelerator at GANIL is a superconducting ion continuous wave LINAC with two associated experimental areas. Mechanical engineers have been highly involved in the design of SPIRAL2 equipments since the beginning of the project in 2004. During the development phase, Computer Aided Design and calculation codes have been used throughout the complete process : from the ion sources, the LINAC, the beam transport lines and the experimental halls equipped with detectors. SPIRAL2 has to meet different safety requirements, among which seismic hazard. This involves justifying that the integrity of the radiologic containment barrier is always maintained in case of earthquake. This paper reports the improvement in design and calculation methods performed by GANIL engineers to meet the seismic safety requirements, specificly the non-missility feature of the equpiment. The modal-spectral simulations, used to demonstrate the mechanical strength of equipments in case of earthquakes, was an important part of this design activity in the past 10 years New methods have been used to calculate welds, fasteners and the ground anchor of the structural supports of the heaviest equipments.
C. Barthe-Dejean, F. Lutton, « Guide methodologique pour Calculs de Tenue aux Séismes des équipements mécaniques », Note STP-535-A

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI11

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Received ※ 14 August 2022 — Revised ※ 19 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 02 September 2022

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MOPORI12

Development of Commercial RFQ Toward CW Applications

255

MOOPA08

use link to see paper's listing under its alternate paper code

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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MOPORI13

On the UNILAC Pulsed Gas Stripper at GSI

258

P. Gerhard, M.T. Maier
GSI, Darmstadt, Germany

The UNILAC will serve as injector linac for heavy ion beams for the future FAIR, with the commissioning being anticipated in 2025. One of the crucial steps in the course of acceleration along the UNILAC is the stripping of the ions by a gas stripper in front of the main linac. Its efficiency is decisive in reaching the intensities required and may be increased by more than 50% by introducing hydrogen as stripping target, instead of the nitrogen used so far. This requires the stripper to be operated in a pulsed mode, since otherwise the pumping speed is not sufficient to maintain suitable vacuum conditions. The proof of principle was demonstrated in 2016*. A dedicated project aims for a setup suitable for routine operation. Main issues are safety, reliability and automated operation. We report on the development done since 2016 and give an overview of the realisation coming within the next few years. Results from systematic measurements on the properties of the valves and their impact on the properties of the stripping target are presented.
* P. Scharrer et al., Developments on the 1.4 MeV/u Pulsed Gas Stripper Cell, in Proc. LINAC2016, East Lansing, MI, USA, Sep. 2016. https://doi.org/10.18429/JACoW-LINAC2016-TUOP03

Poster MOPORI13 [1.908 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI13

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Received ※ 05 August 2022 — Accepted ※ 14 August 2022 — Issue date ※ 02 September 2022

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MOPORI15

Update of Adjustable PMQ Lens

262

Y. Iwashita
Kyoto University, Research Reactor Institute, Osaka, Japan
Y. Fuwa
JAEA/J-PARC, Tokai-mura, Japan
T. Hosokai
ISIR, Osaka, Japan
D. Oumbarek Espinos
Osaka University, Graduate School of Engineering, Osaka, Japan

Gluckstern’s adjustable permanent magnet quadrupole (PMQ) lens based on five rings is revisited to achieve a compact focusing system for laser-accelerated beams. The first prototype was fabricated for bore diameter of 50 mm. The integrated gradient was up to 6.8 T. A new PMQ with a bore diameter of 25 mm is under fabrication based on the same geometry. While the first prototype unit was developed for the final focus magnet of the ILC, the sec-ond unit is the first doublet element for laser-accelerated electron beam focusing to be combined with this first unit. The current status of the development is reported.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI15

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Received ※ 01 September 2022 — Revised ※ 03 September 2022 — Accepted ※ 05 September 2022 — Issue date ※ 15 September 2022

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MOPORI17

The ESS Fast Beam Interlock System: First Experience of Operating With Proton Beam

265

S. Gabourin, M. Carroll, S. Kövecses de Carvalho, A. Nordt, S. Pavinatopresenter, K. Rosquist
ESS, Lund, Sweden

The European Spallation Source (ESS), Sweden, currently in its early operation phase, aims to be the most powerful neutron source in the world. Proton beam pulses are accelerated and sent to a rotating tungsten target, where neutrons are generated via the spallation effect. The damage potential of the ESS proton beam is high and melting of copper or steel can happen within less than 5 microseconds. Therefore, highly reliable and fast machine protection (MP) systems have been designed and deployed. The core system of ESS Machine Protection is the Fast Beam Interlock System (FBIS), based on FPGA technology. FBIS collects data from all relevant accelerator and target systems through 300 direct inputs and decides whether beam operation can start or must stop. The architecture is based on two main building blocks: Decision Logic Node (DLN), executing the protection logic and realizing interfaces to Higher-Level Safety, Timing System and EPICS Control System. The second block, the Signal Condition Unit (SCU), implements the interface between FBIS inputs/outputs and DLNs. This paper gives an overview on FBIS and a summary on its performance during beam commissioning phases since 2021.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI17

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Received ※ 19 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 03 September 2022

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MOPORI18

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

268

S. Wilde, K.J. Middleman, M.D. Pendleton, J.O.W. Poyntonpresenter
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

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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

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]

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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

275

SUPCRI07

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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]

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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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MOPORI23

High-Power Testing Results of X-Band RF-Window and 45 Degrees Spiral Load

279

M. Boronat, H. Bursali, N. Catalán Lasheras, A. Grudiev, G. McMonagle, I. Syratchev
CERN, Meyrin, Switzerland

The X-Band test facilities at CERN have been running for some years now qualifying CLIC structure prototypes but also developing and testing high power general-purpose X-Band components, used in a wide range of applications. Driven by operational needs, several components have been redesigned and tested aiming to optimize the reliability and the compactness of the full system and therefore enhancing the accessibility of this technology inside and outside CERN. To this extent, a new high-power RF-window has been designed and tested aiming to avoid unnecessary venting of high-power sections already conditioned, easing the interventions, and protecting the klystrons. A new spiral load prototype has also been designed, built, and tested, optimizing the compactness, and improving the fabrication process. In these pages, the design and manufacturing for each component will be shortly described, along with the last results on the high-power testing.

Poster MOPORI23 [2.275 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI23

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Received ※ 24 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 31 August 2022

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MOPORI24

Monte Carlo Model of High-Voltage Conditioning and Operation

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

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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

287

SUPCRI02

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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

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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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