IPAC2022 - Classification: MC7: Accelerator Technology / T31: Subsystems, Technology and Components, Other

Paper	Title	Page
TUOXSP3	Evaluation of Geometrical Precision and Surface Roughness Quality for the Additively Manufactured Radio Frequency Quadrupole Prototype	787
	T. Torims, D. Krogere, G. Pikurs, A. Ratkus Riga Technical University, Riga, Latvia A. Cherif, M. Vretenar CERN, Meyrin, Switzerland N. Delerue Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France M. Foppa Pedretti, M. Pozzi Rösler Italiana s.r.l., Concorezzo, Italy S. Gruber, E. Lopez Fraunhofer IWS, Dresden, Germany T. Otto TalTech, Tallinn, Estonia M. Thielmann, P. Wagenblast TRUMPF, Ditzingen, Germany M. Vedani POLIMI, Milano, Italy
	A multidisciplinary collaboration within the I.FAST project teamed-up to develop additive manufacturing (AM) technology solutions for accelerators. The first prototype of an AM pure-copper radio frequency quadrupole (RFQ) has been produced, corresponding to 1/4 of a 4-vane RFQ. It was optimised for production with state-of-the-art laser powder bed fusion technology. Geometrical precision and roughness of the critical surfaces were measured. Alt-hough the obtained values were beyond standard RFQ specifications, these first results are promising and con-firmed the feasibility of AM manufactured complex cop-per accelerator cavities. Therefore, further post-processing trials have been conducted with the sample RFQ to im-prove surface roughness. Algorithms for the AM techno-logical processes have also been improved, allowing for higher geometrical precision. This resulted in the design of a full 4-vane RFQ prototype. At the time of the paper submission the full-size RFQ is being manufactured and will undergo through the stringent surface quality meas-urements. This paper is discussing novel technological developments, is providing an evaluation of the obtained surface roughness and geometrical precision as well as outlining the potential post-processing scenarios along with future tests plans. Torims T, et al. First Proof-of-Concept Prototype of an Additive Manufactured Radio Frequency Quadrupole. Instruments. 2021; 5(4):35. https://doi.org/10.3390/instruments5040035
	Slides TUOXSP3 [10.031 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUOXSP3
About •	Received ※ 20 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 10 July 2022
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TUPOMS052	Considerations From Deploying, Commissioning, and Maintaining the Control System for LCLS-II Undulators	1546
	M.A. Montironi, C.J. Andrews, G. Marcus, H.-D. Nuhn SLAC, Menlo Park, California, USA
	Funding: This work was supported by Department of Energy, Office of Basic Energy Sciences, contract DE-AC02-76SF00515 Two new undulator lines have been installed as part of the Linac Coherent Light Source upgrade (LCLSII) at SLAC National Accelerator Laboratory. One undulator line, composed of 21 horizontally polarizing undulator segments, is dedicated to producing Soft X-Rays (SXR). The other line, composed of 32 vertically polarizing undulator segments, is dedicated to producing Hard X-Rays (HXR). The devices were installed, and the control system was deployed in 2019. Commissioning culminated with the achievement of first light from the HXR undulator in the Summer of 2020 and from the SXR undulator in the Fall of 2020. Since then, both undulator lines have been successfully providing x-Rays to user experiments with very limited downtime. In this paper, we first describe the strategies utilized to simplify the deployment, commissioning, and maintenance of the control system. Such strategies include scripts for automated components calibration and monitoring, a modular software structure, and debugging manuals for accelerator operators. Then, we discuss lessons learned which could be applicable to similar projects in the future.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS052
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 26 June 2022
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THPOST025	Operational Experience with the Improved VSR DEMO Collimating Shielded Bellow in BESSY II	2497
	H.-W. Glock, V. Dürr, F. Glöckner, J. Knobloch, M. Ries, A. Vélez HZB, Berlin, Germany J. Knobloch University of Siegen, Siegen, Germany A. Vélez Technical University Dortmund, Dortmund, Germany
	Funding: Work supported by grants of the Helmholtz Association The Collimating Shielded Bellow (CsB) is designed to serve both as a flexible beam pipe connection between two adjacent superconducting cavities as foreseen in VSR DEMO and as a synchrotron light collimator to shield the down-stream cavity from synchrotron radiation. A convoluted inner RF shield was applied to prevent fundamental mode heating of the stainless-steel-made bellow in the cryogenic environment, making the such captured inner volume very difficult to access for inspection and cleaning. A first version of the device was successfully tested as part of the beam pipe of the synchrotron light source BESSY II under regular operation for more than a year. It suffered from an unfavorable long outgassing commissioning. Therefore a detachable design, allowing for rigorous inner surface preparation and cleaning, was built and recently installed in BESSY II. CsB version 2 design and experimental outcomes are described in the paper. First results indicated a significantly improved vacuum commissioning performance, which was confirmed later on.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST025
About •	Received ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 10 July 2022
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THPOST026	Design of the Magnetic Shield for VSR DEMO	2501
	H.-W. Glock, P. Anumula, F. Glöckner, J. Knobloch, F. Pflocksch, A. Vélez HZB, Berlin, Germany J. Knobloch University of Siegen, Siegen, Germany A. Vélez Technical University Dortmund, Dortmund, Germany
	Funding: Work supported by grants of the Helmholtz Association The VSR DEMO module, recently under development at HZB, will house two 4-cell 1.5 GHz superconducting RF cavities with a particularly powerful HOM damping scheme based on five waveguide HOM absorbers per cavity. A magnetic shield made of high-permeable material is needed around the cavities in order to prevent the ambient magnetic field exceeding very few µT thereby causing considerable unwanted RF losses. The shield needs to accommodate the waveguides, the fundamental power coupler, two beam pipes, two He feed / return lines, the tuner and the support structures, whilst being manufacturable and mountable. The paper discusses those difficulties and presents the matured magnetic shield design. Numerical simulations are used to evaluate the efficacy of the shield.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST026
About •	Received ※ 14 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 22 June 2022
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THPOST027	Fabrication of Robust Thermal Transition Modules and First Cryogenic Experiment with the Refurbished COLDDIAG	2505
	H.J. Cha, N. Glamann, A.W. Grau, A.-S. Müller, D. Saez de Jauregui KIT, Eggenstein-Leopoldshafen, Germany
	Funding: This work is supported by the BMBF project 05H18VKRB1 HIRING (Federal Ministry of Education and Research). Two sets of thermal transition modules as a key component for the COLDDIAG (cold vacuum chamber for beam heat load diagnostics) refurbishment were manufactured, based on the previous design study. The modules are installed in the existing COLDDIAG cryostat and tested with an operating temperature of approximately 50 K at both a cold bore and a thermal shield. This cool-down experiment is a preliminary investigation aiming at beam heat-load studies at the FCC-hh where the beam screens will be operated at almost the same temperature. In this contribution, we report the fabrication processes of the mechanically robust transition modules and the first thermal measurement results with the refurbished COLDDIAG in a cryogenic environment. The static heat load in the refurbished cryostat remains unchanged, compared to that in the former one (4-K cold bore and 50-K shield with thin transitions), despite the increase in the transition thickness. It originates from the identical temperature at the cold bore and the shield, which can theoretically allow the heat intakes by thermal conduction and radiation between them to vanish.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST027
About •	Received ※ 16 May 2022 — Accepted ※ 13 June 2022 — Issue date ※ 10 July 2022
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THPOST029	Upgrade of the Slow Extraction System of the Heidelberg Ion-Beam Therapy Centre’s Synchrotron	2509
	E. Feldmeier, R. Cee, E.C. Cortés García, M. Galonska, Th. Haberer, M. Hun, A. Peters, S. Scheloske, C. Schömers HIT, Heidelberg, Germany
	The Heidelberg Ion-Beam Therapy Centre HIT consists of a linear accelerator and a synchrotron to provide carbon ions, helium ions and protons for the clinical use as well as oxygen ions for experiments. The RF-KO slow extraction method is used to extract the particles from the synchrotron. To improve the spill quality of the extracted beam a new RF-signal was investigated which increases the R-value from 92.5% to 97,5%. The signal is a multiband RF signal broadened with a random BPSK at 3 frequency bands.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST029
About •	Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 24 June 2022
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THPOST030	Laser Instrumentation and Insertion Device Measurement System	2513
	R. Khullar, S.M. Khan, G. Mishra Devi Ahilya University, Indore, India M. Gehlot MAX IV Laboratory, Lund University, Lund, Sweden H. Jeevakhan NITTTR, Bhopal, India
	In this paper, we discuss the Hall probe, pulsed wire and stretched wire magnetic measurement systems indigenously developed and installed at the university laboratory at Devi Ahilya Vishwa Vidyalaya, Indore, India. The laser instrumentation such as position measuring detector, laser scanning micrometre, Wollaston interferometer and Michelson interferometer improves the Hall probe sledge alignment and magnet alignment in the undulator thus improves magnet measurement accuracy. The salient features with design specifics of the laser instrumentation along with magnetic measurement system parameters are described with context to some prototype undulators designed and developed in the laboratory.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST030
About •	Received ※ 04 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 24 June 2022
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THPOST034	Development of Magnetic Harmonics Measurement System for Small Aperture Magnets	2517
SUSPMF122	use link to see paper's listing under its alternate paper code
	J.M. Hwang, J. Bahng Korea University Sejong Campus, Sejong, Republic of Korea E.-S. Kim KUS, Sejong, Republic of Korea
	Storage ring has been improved to achieve high brightness of x-ray light source by making beam size and beam emittance smaller and enlarging the beam intensity. To achieve requirements such as a small beam emittance, the magnets need to have a larger magnetic field gradient and complex function with small aperture size. Since the complex structure and small beam size accompany with large errors in beam dynamics by high order field distortion of the magnets, it is important to measure the harmonics of the magnet in order to measure and improve it. Traditional field measurement methods such as hall probe and rotating loop have difficulty in measuring the harmonics of a magnet with a small aperture due to restrictions that physical size of the hall sensor and loop-card respectively. We developed Single Stretched Wire (SSW) method for the magnetic field measurement method on a small aperture magnet, in particular harmonics of the magnet. The system consists of a thin wire, accurate actuator system, and voltmeter. We describe the development of the SSW system and the result of the performance test by using our system in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST034
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 02 July 2022
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THPOST035	Status of the Engineering Design of the IFMIF-DONES High Energy Beam Transport Line and Beam Dump System	2520
	D. Sánchez-Herranz, O. Nomen, M. Sanmartí, B.K. Singh IREC, Sant Adria del Besos, Spain F. Arranz, C. Oliver, I. Podadera CIEMAT, Madrid, Spain P. Cara IFMIF/EVEDA, Rokkasho, Japan V. Hauer KIT, Eggenstein-Leopoldshafen, Germany F. Ogando UNED, Madrid, Spain D. Sánchez-Herranz UGR, Granada, Spain
	Funding: Work performed within framework of EUROfusion Consortium, funded by European Union via Euratom Research & Training Programme (Grant Agreement 101052200’EUROfusion). Views & opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither European Union nor European Commission can be held responsible for them. IFMIF-DONES plant (International Fusion Materials Irradiation Facility ’ DEMO Oriented Neutron Source) will be an installation located in the south of Spain at Granada. Its objective is the fusion material testing by the generation of a neutron flux with a broad energy distribution covering the typical neutron spectrum of a (D-T) fusion reactor. This is achieved by the Li(d, xn) nuclear reactions occurring in a liquid lithium target where a 40 MeV at 125 mA deuteron beam with a variable rectangular beam footprint between 100mm x 50mm and 200mm x 50mm collides. The accelerator system is in charge of providing such high energy deuterons in order to produce the required neutron flux. The High Energy Beam Transport line is the last subsystem of the IFMIF-DONES accelerator and its main functions are to guide the deuteron beam towards the liquid lithium target and to shape it with the required rectangular reference beam footprint. The present work details the status of the HEBT engineering design, including beam dynamics, vacuum configuration, radioprotection, beam diagnostics devices and remote handling analyses performed detailing the layout and integration.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST035
About •	Received ※ 19 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 14 June 2022
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THPOST037	Analysis with MECAmaster on the Chain of Design Tolerances for the Target Systems at the European Spallation Source - ESS	2524
	A. Bignami, N. Gazis, S. Ghatnekar Nilsson ESS, Lund, Sweden B. Nicquevert CERN, Meyrin, Switzerland
	The European Spallation Source - ESS, has achieved its major construction in Lund, Sweden and is currently continuing in parallel to commissioning its first systems. ESS is characterized by installing and commissioning the most powerful proton LINear ACcelerator (LINAC) designed for neutron production and a 5MW Target system for the production of pulsed neutrons from spallation. The highly challenging and complex design of the Target and Neutron Scattering System (NSS) requires an in-depth analysis of the impact of the stringent manufacturing requirements and tight design tolerances. A campaign of several MECAmaster simulations was performed by ESS Target Division (TD) and Engineering and Integration Support (EIS) Division, focusing on those components that successively come close to their installation and are known for their criticality in terms of achieving the final installation tolerances. The aim of this current study is to investigate and statistically list the possibilities of eventual criticality on the assembly and installation processes, allowing for potential design optimization, tooling implementation and adjustment of the installation procedures.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST037
About •	Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 02 July 2022
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THPOST039	SPS Beam Dump System (SBDS) Commissioning After Relocation and Upgrade	2530
	P. Van Trappen, E. Carlier, L. Ducimetière, V. Namora, V. Senaj, F.M. Velotti, N. Voumard CERN, Meyrin, Switzerland
	In order to overcome several machine limitations, the SBDS has been relocated from LSS1 (Long Straight Section 1) to LSS5 during LS2 (Long Shutdown 2) with an important upgrade of the extraction kicker installation. An additional vertical deflection kicker magnet (MKDV) was produced and installed while the high voltage (HV) pulse generators have been upgraded by changing gas-discharge switches (thyratrons and ignitrons) to semiconductor stacks operating in oil. Furthermore the horizontal sweep generators have been upgraded to allow for a lower kick strengths. The controls, previously consolidated during LS1, went through an additional light consolidation phase with among others the upgrade of the trigger & retrigger distribution system and the installation of a new fast-interlocks detection system. This paper describes the commissioning without and with beam and elaborates on the measured improvements and encountered problems with corrective mitigations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST039
About •	Received ※ 07 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 15 June 2022
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THPOST041	Construction and Manufacturing Process of Siam Photon Source II Storage Ring Girder Prototype	2537
	S. Srichan, S. Klinkhieo, M. Phanak, S. Prabngulueam, P. Pruekthaisong, K. Sittisard SLRI, Nakhon Ratchasima, Thailand O. Utke Synchrotron Light Research Institute (SLRI), Muang District, Thailand
	The Siam Photon Source II storage ring is designed with low emittance. This new machine requires a high performance support system and a precise alignment capability. In order to meet these requirements, we have planned for construction of a half-cell component prototype. In the end of 2021, we completed the first girder prototype. This report will describe construction and manufacturing process.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST041
About •	Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022
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THPOST045	Temperature Dependent Effects on RF Surface Resistivity	2540
	G.E. Lawler, A. Fukasawa, N. Majernik, J.B. Rosenzweig UCLA, Los Angeles, California, USA
	Funding: This work was supported by DOE Contract DE-SC0020409 A promising future for linear accelerators such as compact free electron lasers and electron positron colliders is higher gradient RF cavities enabled by cryogenic temperature operation. Breakdown rates have been shown empirically to be significantly reduced at low temperatures allowing for higher gradient. The surface physics associated with this observation is complicated and there many remain questions as to the exact phenomena responsible. One major figure of merit that can better inform the theory of breakdown is the RF surface resistivity which can be used to compute for example the RF pulse heating during operation. We then use techniques developed for previous Xband and Sband low power surface resistivity measurement by way of temperature dependent quality factor measurements to study Cband cavities. We first present a review of low temperature effects that may be responsible for the change in surface resistivity at low temperature. We then explain some of the initial measurements of these low power RF quality factor tests and compare them to a review some of the physical phenomena that could determine the low temperature surface effects.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST045
About •	Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 20 June 2022
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THPOST048	RHIC Machine Protection System Upgrades	2548
	M. Valette, D. Bruno, K.A. Drees, P.S. Dyer, R.L. Hulsart, J.S. Laster, J. Morris, G. Robert-Demolaize, J. Sandberg, C. Schultheiss, T.C. Shrey, G.M. Tustin BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. ’In order to protect the future sPHENIX detector from spontaneous and asynchronous firing of one of the five RHIC abort kickers, mechanical relays were added to the triggering channel for each of them. The mechanical relays add several milliseconds to the delay between the detection of a failure or beam loss and the beam being safely disposed of. In order to account for this delay new inputs were included into the RHIC Machine Protection System to ensure detection of abnormal conditions as early as possible. These inputs include system diagnostics and beam measurements such as Beam Position Monitor signals. In this paper we detail the upgrades that will allow reliable operations with high intensity and high energy ion beams and the new detector as well as related operational challenges and how they were addressed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST048
About •	Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 16 June 2022
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THPOPT037	Ceramics Evaluation for MW-Power Coaxial Windows, Operating in UHF Frequency Range	2668
	S.V. Kutsaev, R.B. Agustsson, P.R. Carriere, N.G. Matavalam, A.Yu. Smirnov, S.U. Thielk RadiaBeam, Santa Monica, California, USA A.A. Haase SLAC, Menlo Park, California, USA T.W. Hall, D. Kim, J.T.M. Lyles, K.E. Nichols LANL, Los Alamos, New Mexico, USA
	Funding: This work was supported by the U.S. Department of Energy, Office of Basic Energy Science, under SBIR grant DE- SC0021552 Modern accelerator facilities require reliable high-power RF components. The RF vacuum window is a critical part of the waveguide couplers to the accelerating cavities. It is the point where the RF feed crosses the vacuum boundary and thus forms part of the confinement barrier. RF windows must be designed to have low power dissipation inside their ceramic, be resistant to mechanical stresses, and free of discharges. In this paper, we report on the evaluation of three different ceramic candidates for high power RF windows. These materials have low loss tangents, low secondary electron yield (SEY), and large thermal expansion coefficients. The acquired materials were inspected, coated, and measured to select the optimal set.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT037
About •	Received ※ 01 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 04 July 2022
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THPOTK026	Development and Test of a Program for Automatic Conditioning of Room Temperature Cavities	2823
	K. Kümpel, M. Märcz, H. Podlech, A. Rüffer, C. Wagner, S.R. Wagner IAP, Frankfurt am Main, Germany H. Podlech HFHF, Frankfurt am Main, Germany
	The conditioning of room temperature cavities is a time-consuming process that can take several weeks and requires the supervision of experienced experimenters. To simplify this process for future cavities, a program is currently being developed at the IAP Frankfurt that will simplify the experimenter’s work and eventually take it over completely. This paper describes the basic setup of the program so far, as well as the tests performed on different cavities so far. In addition, an outlook for the next development steps and their application is given.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK026
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
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THPOTK050	CFD Studies of the Convective Heat Transfer Coefficients and Pressure Drops in Geometries Applied to Water Cooling Channels of the Crotch Absorbers of ALBA Synchrotron Light Source	2887
SUSPMF123	use link to see paper's listing under its alternate paper code
	S. Grozavu, G.A. Raush ESEIAAT, Terrassa, Spain J.J. Casas, C. Colldelram, M. Quispe ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	Currently, the storage ring vacuum chambers of ALBA are protected by 156 crotch absorbers made of copper and Glidcop. After more than 10 years of operation as a third-generation light source, the ALBA II project arose, aiming to transform this infrastructure into a fourth-generation synchrotron. This introduces new challenges in terms of the thermal and mechanical design of the future absorbers. The absorbers’ cooling channels consist of a set of 8-mm-diameter holes parallel to each other and drilled into the body of the absorbers. In each hole, there is a 6x1 mm stainless steel concentric inner tube coiled in spiral wires, whose aim is to enhance the heat transfer. The convective heat transfer coefficients used for the original design of the absorbers come from experimental correlations from the literature, and are applied as a global value for the whole system. In this work, Heat Transfer-Computational Fluid Dynamics (HT-CFD) studies of the convective heat transfer coefficients and pressure gradients in three different cooling channel geometries are carried out, aiming at leading the way of designing the cooling systems toward the CFD simulations rather than applying global experimental values. This information will be useful for the sizing of the new absorbers for the ALBA II project.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK050
About •	Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
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THPOTK057	ESS RFQ Experimental Modal Analysis	2907
	E. Trachanas, A. Bignami, N. Gazis, B. Jones ESS, Lund, Sweden
	The European Spallation Source-ESS, which is currently under construction and commissioning at Lund, Sweden is a neutron source that consists of a 2 GeV linear accelerator (LINAC) accelerating a proton beam to a solid Tungsten (W) target. The proton beam is produced by the Ion Source (ISRC) and transported through the Low Energy Beam Transport (LEBT) to the Radio Frequency Quadrupole (RFQ) that will then focus, bunch and accelerate it to 3.6 MeV. The RFQ beam commissioning started in October 2021, following the RF conditioning phase in summer 2021. This current work presents an experimental modal analysis performed on RFQ including the comparative analysis with the modal finite element simulation using the ANSYS software suite. Measurements were performed using accelerometer sensors connected to a data acquisition system excited with an impact hammer. Geophones were used in parallel to the modal measurements in order to monitor the seismic background of the accelerator tunnel. Acquired data were post-processed and analysed with dedicated software, juxtaposed with simulated results in order to determine the resonance frequencies, structural deformation patterns (mode shapes) and error margin between experimental and simulated results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK057
About •	Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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FRIXSP1	Low-Emittance Compact RF Electron Gun with a Gridded Thermionic Cathode	3124
	T. Asaka JASRI/SPring-8, Hyogo-ken, Japan
	A new type of rf electron gun has been developed to generate a stable electron beam with a low-emittance of ~1 um.rad, that can be injected into SX-FEL and DLSR, without using a large UV laser system nor an ultra-high voltage pulsers. This electron gun consists of a 50 kV pulsed gun equipped with a commercially available thermionic cathode with grid and a 238-MHz acceleration cavity driven by a 42 kW solid-state amplifier. The system is simple, stable, robust, and of easy-maintenance. To obtain a "grid-transparent" condition, the cathode voltage and the control grid voltage are optimized not to distort the electric field near the grid. To avoid the emittance growth due to the space charge effect, the gun and a special magnetic lens are embedded in the 238-MHz cavity at the shortest distance, and the beam energy is immediately accelerated to 500 kV. The first model of this electron gun has been operated as the 1 GeV injector of the NewSUBARU storage ring. The same electron gun will also be used in the injector linac of the 3 GeV light source under construction in Japan. The talk is expected to include the concept, overall design and the achieved performance.
	Slides FRIXSP1 [2.893 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-FRIXSP1
About •	Received ※ 08 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 19 June 2022 — Issue date ※ 23 June 2022
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Paper

Title

Page

Evaluation of Geometrical Precision and Surface Roughness Quality for the Additively Manufactured Radio Frequency Quadrupole Prototype

787

T. Torims, D. Krogere, G. Pikurs, A. Ratkus
Riga Technical University, Riga, Latvia
A. Cherif, M. Vretenar
CERN, Meyrin, Switzerland
N. Delerue
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
M. Foppa Pedretti, M. Pozzi
Rösler Italiana s.r.l., Concorezzo, Italy
S. Gruber, E. Lopez
Fraunhofer IWS, Dresden, Germany
T. Otto
TalTech, Tallinn, Estonia
M. Thielmann, P. Wagenblast
TRUMPF, Ditzingen, Germany
M. Vedani
POLIMI, Milano, Italy

A multidisciplinary collaboration within the I.FAST project teamed-up to develop additive manufacturing (AM) technology solutions for accelerators. The first prototype of an AM pure-copper radio frequency quadrupole (RFQ) has been produced, corresponding to 1/4 of a 4-vane RFQ*. It was optimised for production with state-of-the-art laser powder bed fusion technology. Geometrical precision and roughness of the critical surfaces were measured. Alt-hough the obtained values were beyond standard RFQ specifications, these first results are promising and con-firmed the feasibility of AM manufactured complex cop-per accelerator cavities. Therefore, further post-processing trials have been conducted with the sample RFQ to im-prove surface roughness. Algorithms for the AM techno-logical processes have also been improved, allowing for higher geometrical precision. This resulted in the design of a full 4-vane RFQ prototype. At the time of the paper submission the full-size RFQ is being manufactured and will undergo through the stringent surface quality meas-urements. This paper is discussing novel technological developments, is providing an evaluation of the obtained surface roughness and geometrical precision as well as outlining the potential post-processing scenarios along with future tests plans.
* Torims T, et al. First Proof-of-Concept Prototype of an Additive Manufactured Radio Frequency Quadrupole. Instruments. 2021; 5(4):35. https://doi.org/10.3390/instruments5040035

Slides TUOXSP3 [10.031 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUOXSP3

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Received ※ 20 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 10 July 2022

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TUPOMS052

Considerations From Deploying, Commissioning, and Maintaining the Control System for LCLS-II Undulators

1546

M.A. Montironi, C.J. Andrews, G. Marcus, H.-D. Nuhn
SLAC, Menlo Park, California, USA

Funding: This work was supported by Department of Energy, Office of Basic Energy Sciences, contract DE-AC02-76SF00515
Two new undulator lines have been installed as part of the Linac Coherent Light Source upgrade (LCLSII) at SLAC National Accelerator Laboratory. One undulator line, composed of 21 horizontally polarizing undulator segments, is dedicated to producing Soft X-Rays (SXR). The other line, composed of 32 vertically polarizing undulator segments, is dedicated to producing Hard X-Rays (HXR). The devices were installed, and the control system was deployed in 2019. Commissioning culminated with the achievement of first light from the HXR undulator in the Summer of 2020 and from the SXR undulator in the Fall of 2020. Since then, both undulator lines have been successfully providing x-Rays to user experiments with very limited downtime. In this paper, we first describe the strategies utilized to simplify the deployment, commissioning, and maintenance of the control system. Such strategies include scripts for automated components calibration and monitoring, a modular software structure, and debugging manuals for accelerator operators. Then, we discuss lessons learned which could be applicable to similar projects in the future.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS052

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 26 June 2022

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THPOST025

Operational Experience with the Improved VSR DEMO Collimating Shielded Bellow in BESSY II

2497

H.-W. Glock, V. Dürr, F. Glöckner, J. Knobloch, M. Ries, A. Vélez
HZB, Berlin, Germany
J. Knobloch
University of Siegen, Siegen, Germany
A. Vélez
Technical University Dortmund, Dortmund, Germany

Funding: Work supported by grants of the Helmholtz Association
The Collimating Shielded Bellow (CsB) is designed to serve both as a flexible beam pipe connection between two adjacent superconducting cavities as foreseen in VSR DEMO and as a synchrotron light collimator to shield the down-stream cavity from synchrotron radiation. A convoluted inner RF shield was applied to prevent fundamental mode heating of the stainless-steel-made bellow in the cryogenic environment, making the such captured inner volume very difficult to access for inspection and cleaning. A first version of the device was successfully tested as part of the beam pipe of the synchrotron light source BESSY II under regular operation for more than a year. It suffered from an unfavorable long outgassing commissioning. Therefore a detachable design, allowing for rigorous inner surface preparation and cleaning, was built and recently installed in BESSY II. CsB version 2 design and experimental outcomes are described in the paper. First results indicated a significantly improved vacuum commissioning performance, which was confirmed later on.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST025

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Received ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 10 July 2022

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THPOST026

Design of the Magnetic Shield for VSR DEMO

2501

H.-W. Glock, P. Anumula, F. Glöckner, J. Knobloch, F. Pflocksch, A. Vélez
HZB, Berlin, Germany
J. Knobloch
University of Siegen, Siegen, Germany
A. Vélez
Technical University Dortmund, Dortmund, Germany

Funding: Work supported by grants of the Helmholtz Association
The VSR DEMO module, recently under development at HZB, will house two 4-cell 1.5 GHz superconducting RF cavities with a particularly powerful HOM damping scheme based on five waveguide HOM absorbers per cavity. A magnetic shield made of high-permeable material is needed around the cavities in order to prevent the ambient magnetic field exceeding very few µT thereby causing considerable unwanted RF losses. The shield needs to accommodate the waveguides, the fundamental power coupler, two beam pipes, two He feed / return lines, the tuner and the support structures, whilst being manufacturable and mountable. The paper discusses those difficulties and presents the matured magnetic shield design. Numerical simulations are used to evaluate the efficacy of the shield.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST026

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Received ※ 14 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 22 June 2022

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THPOST027

Fabrication of Robust Thermal Transition Modules and First Cryogenic Experiment with the Refurbished COLDDIAG

2505

H.J. Cha, N. Glamann, A.W. Grau, A.-S. Müller, D. Saez de Jauregui
KIT, Eggenstein-Leopoldshafen, Germany

Funding: This work is supported by the BMBF project 05H18VKRB1 HIRING (Federal Ministry of Education and Research).
Two sets of thermal transition modules as a key component for the COLDDIAG (cold vacuum chamber for beam heat load diagnostics) refurbishment were manufactured, based on the previous design study. The modules are installed in the existing COLDDIAG cryostat and tested with an operating temperature of approximately 50 K at both a cold bore and a thermal shield. This cool-down experiment is a preliminary investigation aiming at beam heat-load studies at the FCC-hh where the beam screens will be operated at almost the same temperature. In this contribution, we report the fabrication processes of the mechanically robust transition modules and the first thermal measurement results with the refurbished COLDDIAG in a cryogenic environment. The static heat load in the refurbished cryostat remains unchanged, compared to that in the former one (4-K cold bore and 50-K shield with thin transitions), despite the increase in the transition thickness. It originates from the identical temperature at the cold bore and the shield, which can theoretically allow the heat intakes by thermal conduction and radiation between them to vanish.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST027

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Received ※ 16 May 2022 — Accepted ※ 13 June 2022 — Issue date ※ 10 July 2022

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THPOST029

Upgrade of the Slow Extraction System of the Heidelberg Ion-Beam Therapy Centre’s Synchrotron

2509

E. Feldmeier, R. Cee, E.C. Cortés García, M. Galonska, Th. Haberer, M. Hun, A. Peters, S. Scheloske, C. Schömers
HIT, Heidelberg, Germany

The Heidelberg Ion-Beam Therapy Centre HIT consists of a linear accelerator and a synchrotron to provide carbon ions, helium ions and protons for the clinical use as well as oxygen ions for experiments. The RF-KO slow extraction method is used to extract the particles from the synchrotron. To improve the spill quality of the extracted beam a new RF-signal was investigated which increases the R-value from 92.5% to 97,5%. The signal is a multiband RF signal broadened with a random BPSK at 3 frequency bands.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST029

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Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 24 June 2022

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THPOST030

Laser Instrumentation and Insertion Device Measurement System

2513

R. Khullar, S.M. Khan, G. Mishra
Devi Ahilya University, Indore, India
M. Gehlot
MAX IV Laboratory, Lund University, Lund, Sweden
H. Jeevakhan
NITTTR, Bhopal, India

In this paper, we discuss the Hall probe, pulsed wire and stretched wire magnetic measurement systems indigenously developed and installed at the university laboratory at Devi Ahilya Vishwa Vidyalaya, Indore, India. The laser instrumentation such as position measuring detector, laser scanning micrometre, Wollaston interferometer and Michelson interferometer improves the Hall probe sledge alignment and magnet alignment in the undulator thus improves magnet measurement accuracy. The salient features with design specifics of the laser instrumentation along with magnetic measurement system parameters are described with context to some prototype undulators designed and developed in the laboratory.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST030

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Received ※ 04 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 24 June 2022

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THPOST034

Development of Magnetic Harmonics Measurement System for Small Aperture Magnets

2517

SUSPMF122

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J.M. Hwang, J. Bahng
Korea University Sejong Campus, Sejong, Republic of Korea
E.-S. Kim
KUS, Sejong, Republic of Korea

Storage ring has been improved to achieve high brightness of x-ray light source by making beam size and beam emittance smaller and enlarging the beam intensity. To achieve requirements such as a small beam emittance, the magnets need to have a larger magnetic field gradient and complex function with small aperture size. Since the complex structure and small beam size accompany with large errors in beam dynamics by high order field distortion of the magnets, it is important to measure the harmonics of the magnet in order to measure and improve it. Traditional field measurement methods such as hall probe and rotating loop have difficulty in measuring the harmonics of a magnet with a small aperture due to restrictions that physical size of the hall sensor and loop-card respectively. We developed Single Stretched Wire (SSW) method for the magnetic field measurement method on a small aperture magnet, in particular harmonics of the magnet. The system consists of a thin wire, accurate actuator system, and voltmeter. We describe the development of the SSW system and the result of the performance test by using our system in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST034

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 02 July 2022

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THPOST035

Status of the Engineering Design of the IFMIF-DONES High Energy Beam Transport Line and Beam Dump System

2520

D. Sánchez-Herranz, O. Nomen, M. Sanmartí, B.K. Singh
IREC, Sant Adria del Besos, Spain
F. Arranz, C. Oliver, I. Podadera
CIEMAT, Madrid, Spain
P. Cara
IFMIF/EVEDA, Rokkasho, Japan
V. Hauer
KIT, Eggenstein-Leopoldshafen, Germany
F. Ogando
UNED, Madrid, Spain
D. Sánchez-Herranz
UGR, Granada, Spain

Funding: Work performed within framework of EUROfusion Consortium, funded by European Union via Euratom Research & Training Programme (Grant Agreement 101052200’EUROfusion). Views & opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither European Union nor European Commission can be held responsible for them.
IFMIF-DONES plant (International Fusion Materials Irradiation Facility ’ DEMO Oriented Neutron Source) will be an installation located in the south of Spain at Granada. Its objective is the fusion material testing by the generation of a neutron flux with a broad energy distribution covering the typical neutron spectrum of a (D-T) fusion reactor. This is achieved by the Li(d, xn) nuclear reactions occurring in a liquid lithium target where a 40 MeV at 125 mA deuteron beam with a variable rectangular beam footprint between 100mm x 50mm and 200mm x 50mm collides. The accelerator system is in charge of providing such high energy deuterons in order to produce the required neutron flux. The High Energy Beam Transport line is the last subsystem of the IFMIF-DONES accelerator and its main functions are to guide the deuteron beam towards the liquid lithium target and to shape it with the required rectangular reference beam footprint. The present work details the status of the HEBT engineering design, including beam dynamics, vacuum configuration, radioprotection, beam diagnostics devices and remote handling analyses performed detailing the layout and integration.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST035

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Received ※ 19 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 14 June 2022

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THPOST037

Analysis with MECAmaster on the Chain of Design Tolerances for the Target Systems at the European Spallation Source - ESS

2524

A. Bignami, N. Gazis, S. Ghatnekar Nilsson
ESS, Lund, Sweden
B. Nicquevert
CERN, Meyrin, Switzerland

The European Spallation Source - ESS, has achieved its major construction in Lund, Sweden and is currently continuing in parallel to commissioning its first systems. ESS is characterized by installing and commissioning the most powerful proton LINear ACcelerator (LINAC) designed for neutron production and a 5MW Target system for the production of pulsed neutrons from spallation. The highly challenging and complex design of the Target and Neutron Scattering System (NSS) requires an in-depth analysis of the impact of the stringent manufacturing requirements and tight design tolerances. A campaign of several MECAmaster simulations was performed by ESS Target Division (TD) and Engineering and Integration Support (EIS) Division, focusing on those components that successively come close to their installation and are known for their criticality in terms of achieving the final installation tolerances. The aim of this current study is to investigate and statistically list the possibilities of eventual criticality on the assembly and installation processes, allowing for potential design optimization, tooling implementation and adjustment of the installation procedures.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST037

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Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 02 July 2022

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THPOST039

SPS Beam Dump System (SBDS) Commissioning After Relocation and Upgrade

2530

P. Van Trappen, E. Carlier, L. Ducimetière, V. Namora, V. Senaj, F.M. Velotti, N. Voumard
CERN, Meyrin, Switzerland

In order to overcome several machine limitations, the SBDS has been relocated from LSS1 (Long Straight Section 1) to LSS5 during LS2 (Long Shutdown 2) with an important upgrade of the extraction kicker installation. An additional vertical deflection kicker magnet (MKDV) was produced and installed while the high voltage (HV) pulse generators have been upgraded by changing gas-discharge switches (thyratrons and ignitrons) to semiconductor stacks operating in oil. Furthermore the horizontal sweep generators have been upgraded to allow for a lower kick strengths. The controls, previously consolidated during LS1, went through an additional light consolidation phase with among others the upgrade of the trigger & retrigger distribution system and the installation of a new fast-interlocks detection system. This paper describes the commissioning without and with beam and elaborates on the measured improvements and encountered problems with corrective mitigations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST039

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Received ※ 07 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 15 June 2022

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THPOST041

Construction and Manufacturing Process of Siam Photon Source II Storage Ring Girder Prototype

2537

S. Srichan, S. Klinkhieo, M. Phanak, S. Prabngulueam, P. Pruekthaisong, K. Sittisard
SLRI, Nakhon Ratchasima, Thailand
O. Utke
Synchrotron Light Research Institute (SLRI), Muang District, Thailand

The Siam Photon Source II storage ring is designed with low emittance. This new machine requires a high performance support system and a precise alignment capability. In order to meet these requirements, we have planned for construction of a half-cell component prototype. In the end of 2021, we completed the first girder prototype. This report will describe construction and manufacturing process.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST041

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Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022

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THPOST045

Temperature Dependent Effects on RF Surface Resistivity

2540

G.E. Lawler, A. Fukasawa, N. Majernik, J.B. Rosenzweig
UCLA, Los Angeles, California, USA

Funding: This work was supported by DOE Contract DE-SC0020409
A promising future for linear accelerators such as compact free electron lasers and electron positron colliders is higher gradient RF cavities enabled by cryogenic temperature operation. Breakdown rates have been shown empirically to be significantly reduced at low temperatures allowing for higher gradient. The surface physics associated with this observation is complicated and there many remain questions as to the exact phenomena responsible. One major figure of merit that can better inform the theory of breakdown is the RF surface resistivity which can be used to compute for example the RF pulse heating during operation. We then use techniques developed for previous Xband and Sband low power surface resistivity measurement by way of temperature dependent quality factor measurements to study Cband cavities. We first present a review of low temperature effects that may be responsible for the change in surface resistivity at low temperature. We then explain some of the initial measurements of these low power RF quality factor tests and compare them to a review some of the physical phenomena that could determine the low temperature surface effects.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST045

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Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 20 June 2022

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THPOST048

RHIC Machine Protection System Upgrades

2548

M. Valette, D. Bruno, K.A. Drees, P.S. Dyer, R.L. Hulsart, J.S. Laster, J. Morris, G. Robert-Demolaize, J. Sandberg, C. Schultheiss, T.C. Shrey, G.M. Tustin
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
’In order to protect the future sPHENIX detector from spontaneous and asynchronous firing of one of the five RHIC abort kickers, mechanical relays were added to the triggering channel for each of them. The mechanical relays add several milliseconds to the delay between the detection of a failure or beam loss and the beam being safely disposed of. In order to account for this delay new inputs were included into the RHIC Machine Protection System to ensure detection of abnormal conditions as early as possible. These inputs include system diagnostics and beam measurements such as Beam Position Monitor signals. In this paper we detail the upgrades that will allow reliable operations with high intensity and high energy ion beams and the new detector as well as related operational challenges and how they were addressed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST048

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Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 16 June 2022

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THPOPT037

Ceramics Evaluation for MW-Power Coaxial Windows, Operating in UHF Frequency Range

2668

S.V. Kutsaev, R.B. Agustsson, P.R. Carriere, N.G. Matavalam, A.Yu. Smirnov, S.U. Thielk
RadiaBeam, Santa Monica, California, USA
A.A. Haase
SLAC, Menlo Park, California, USA
T.W. Hall, D. Kim, J.T.M. Lyles, K.E. Nichols
LANL, Los Alamos, New Mexico, USA

Funding: This work was supported by the U.S. Department of Energy, Office of Basic Energy Science, under SBIR grant DE- SC0021552
Modern accelerator facilities require reliable high-power RF components. The RF vacuum window is a critical part of the waveguide couplers to the accelerating cavities. It is the point where the RF feed crosses the vacuum boundary and thus forms part of the confinement barrier. RF windows must be designed to have low power dissipation inside their ceramic, be resistant to mechanical stresses, and free of discharges. In this paper, we report on the evaluation of three different ceramic candidates for high power RF windows. These materials have low loss tangents, low secondary electron yield (SEY), and large thermal expansion coefficients. The acquired materials were inspected, coated, and measured to select the optimal set.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT037

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Received ※ 01 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 04 July 2022

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THPOTK026

Development and Test of a Program for Automatic Conditioning of Room Temperature Cavities

2823

K. Kümpel, M. Märcz, H. Podlech, A. Rüffer, C. Wagner, S.R. Wagner
IAP, Frankfurt am Main, Germany
H. Podlech
HFHF, Frankfurt am Main, Germany

The conditioning of room temperature cavities is a time-consuming process that can take several weeks and requires the supervision of experienced experimenters. To simplify this process for future cavities, a program is currently being developed at the IAP Frankfurt that will simplify the experimenter’s work and eventually take it over completely. This paper describes the basic setup of the program so far, as well as the tests performed on different cavities so far. In addition, an outlook for the next development steps and their application is given.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK026

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Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022

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THPOTK050

CFD Studies of the Convective Heat Transfer Coefficients and Pressure Drops in Geometries Applied to Water Cooling Channels of the Crotch Absorbers of ALBA Synchrotron Light Source

2887

SUSPMF123

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S. Grozavu, G.A. Raush
ESEIAAT, Terrassa, Spain
J.J. Casas, C. Colldelram, M. Quispe
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

Currently, the storage ring vacuum chambers of ALBA are protected by 156 crotch absorbers made of copper and Glidcop. After more than 10 years of operation as a third-generation light source, the ALBA II project arose, aiming to transform this infrastructure into a fourth-generation synchrotron. This introduces new challenges in terms of the thermal and mechanical design of the future absorbers. The absorbers’ cooling channels consist of a set of 8-mm-diameter holes parallel to each other and drilled into the body of the absorbers. In each hole, there is a 6x1 mm stainless steel concentric inner tube coiled in spiral wires, whose aim is to enhance the heat transfer. The convective heat transfer coefficients used for the original design of the absorbers come from experimental correlations from the literature, and are applied as a global value for the whole system. In this work, Heat Transfer-Computational Fluid Dynamics (HT-CFD) studies of the convective heat transfer coefficients and pressure gradients in three different cooling channel geometries are carried out, aiming at leading the way of designing the cooling systems toward the CFD simulations rather than applying global experimental values. This information will be useful for the sizing of the new absorbers for the ALBA II project.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK050

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Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022

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THPOTK057

ESS RFQ Experimental Modal Analysis

2907

E. Trachanas, A. Bignami, N. Gazis, B. Jones
ESS, Lund, Sweden

The European Spallation Source-ESS, which is currently under construction and commissioning at Lund, Sweden is a neutron source that consists of a 2 GeV linear accelerator (LINAC) accelerating a proton beam to a solid Tungsten (W) target. The proton beam is produced by the Ion Source (ISRC) and transported through the Low Energy Beam Transport (LEBT) to the Radio Frequency Quadrupole (RFQ) that will then focus, bunch and accelerate it to 3.6 MeV. The RFQ beam commissioning started in October 2021, following the RF conditioning phase in summer 2021. This current work presents an experimental modal analysis performed on RFQ including the comparative analysis with the modal finite element simulation using the ANSYS software suite. Measurements were performed using accelerometer sensors connected to a data acquisition system excited with an impact hammer. Geophones were used in parallel to the modal measurements in order to monitor the seismic background of the accelerator tunnel. Acquired data were post-processed and analysed with dedicated software, juxtaposed with simulated results in order to determine the resonance frequencies, structural deformation patterns (mode shapes) and error margin between experimental and simulated results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK057

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Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022

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FRIXSP1

Low-Emittance Compact RF Electron Gun with a Gridded Thermionic Cathode

3124

T. Asaka
JASRI/SPring-8, Hyogo-ken, Japan

A new type of rf electron gun has been developed to generate a stable electron beam with a low-emittance of ~1 um.rad, that can be injected into SX-FEL and DLSR, without using a large UV laser system nor an ultra-high voltage pulsers. This electron gun consists of a 50 kV pulsed gun equipped with a commercially available thermionic cathode with grid and a 238-MHz acceleration cavity driven by a 42 kW solid-state amplifier. The system is simple, stable, robust, and of easy-maintenance. To obtain a "grid-transparent" condition, the cathode voltage and the control grid voltage are optimized not to distort the electric field near the grid. To avoid the emittance growth due to the space charge effect, the gun and a special magnetic lens are embedded in the 238-MHz cavity at the shortest distance, and the beam energy is immediately accelerated to 500 kV. The first model of this electron gun has been operated as the 1 GeV injector of the NewSUBARU storage ring. The same electron gun will also be used in the injector linac of the 3 GeV light source under construction in Japan. The talk is expected to include the concept, overall design and the achieved performance.

Slides FRIXSP1 [2.893 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-FRIXSP1

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Received ※ 08 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 19 June 2022 — Issue date ※ 23 June 2022

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