SRF2019 - List of Keywords (cryogenics)

Paper	Title	Other Keywords	Page
MOFAA3	The FRIB SC-Linac - Installation and Phased Commissioning	cryomodule, MMI, cavity, linac	12
	J. Wei, H. Ao, S. Beher, B. Bird, N.K. Bultman, F. Casagrande, D. Chabot, W. Chang, S. Cogan, C. Compton, J. Curtin, K.D. Davidson, E. Daykin, K. Elliott, A. Facco, A. Fila, V. Ganni, A. Ganshyn, P.E. Gibson, T. Glasmacher, I. Grender, W. Hartung, L. Hodges, K. Holland, H.-C. Hseuh, A. Hussain, M. Ikegami, S. Jones, T. Kanemura, S.H. Kim, P. Knudsen, M.G. Konrad, J. LeTourneau, Z. Li, S.M. Lidia, G. Machicoane, P. Manwiller, F. Marti, T. Maruta, E.S. Metzgar, S.J. Miller, D.G. Morris, C. Nguyen, K. Openlander, P.N. Ostroumov, A.S. Plastun, J.T. Popielarski, L. Popielarski, J. Priller, M.A. Reaume, H.T. Ren, T. Russo, K. Saito, M. Shuptar, J.W. Stetson, D.R. Victory, R. Walker, X. Wang, J.D. Wenstrom, M. Wright, M. Xu, T. Xu, Y. Yamazaki, Q. Zhao, S. Zhao FRIB, East Lansing, Michigan, USA K. Dixon, M. Wiseman JLab, Newport News, Virginia, USA A. Facco INFN/LNL, Legnaro (PD), Italy K. Hosoyama KEK, Ibaraki, Japan M.P. Kelly ANL, Lemont, Illinois, USA R.E. Laxdal TRIUMF, Vancouver, Canada
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. The Facility for Rare Isotope Beams (FRIB) superconducting (SC) driver linac is designed to accelerate all stable ions including uranium to energies above 200 MeV/u primarily with 46 cryomodules containing 324 quarter-wave resonators (QWR) and half-wave (HWR) resonators. With the newly commissioned helium refrigeration system supplying liquid helium to the QWR and solenoids, heavy ion beams including Ne, Ar, Kr and Xe were accelerated to the charge stripper location above 20 MeV/u with the first linac segment consisting of 15 cryomodules containing 10⁴ QWRs of β=0.041 and 0.085 and 39 solenoids. Installation of cryomodules with β=0.29 and 0.53 HWRs is proceeding in parallel. Development of β=0.65 elliptical resonators is on-going supporting the FRIB energy upgrade to 400 MeV/u. This paper summarizes the SC-linac installation and phased commissioning status that is on schedule and on budget to the FRIB project.
	Slides MOFAA3 [46.571 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOFAA3
About •	paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
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MOP035	Cryogenic Infrastructure at BESSY II – Current Installations and Future Developments	cavity, storage-ring, gun, radiation	131
	S. Heling, W. Anders, J. Heinrich, A. Hellwig, K. Janke, S. Rotterdam HZB, Berlin, Germany
	In Berlin-Adlershof the Helmholtz-Zentrum Berlin (HZB) is operating the synchrotron radiation source BESSY II. Two superconducting wave-length shifter magnets are built-in the storage ring of BESSY II which are cooled with liquid helium. Additionally several test facilities for superconducting cavities are operated at HZB needing helium at 1.8 K. The required helium is supplied by two helium liquefiers. Parallel to operation of the existing facilities the BERLinPro project will qualify as test facility for ERL science and technology. In order to guarantee the required supply with helium at different temperature levels one of the existing helium liquefiers has been relocated to the new accelerator building and the existing cryogenic infrastructure has been upgraded with a new 10 000 L dewar, three valve boxes, a cold compressor box, warm pumps and a 80 K helium system. This paper specifies the setup of the above described helium cryoplants in detail and gives insight into the challenges of development. The paper concludes with an outlook of the upcoming developments of the cryogenic infrastructure at HZB.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP035
About •	paper received ※ 20 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
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MOP076	Fundamental Power Coupler Design for a 325 MHz Balloon SSR Cavity	cavity, multipactoring, vacuum, simulation	252
	R.E. Laxdal, Y. Ma, B. Matheson, B.S. Waraich, Z.Y. Yao, V. Zvyagintsev TRIUMF, Vancouver, Canada
	TRIUMF has designed, fabricated and tested the first balloon variant of the single spoke resonator at 325 MHz and β=0.3. TRIUMF has also designed a 6 kW fundamental power coupler as part of the development. The design of the coupler will be presented.
	Poster MOP076 [1.282 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP076
About •	paper received ※ 24 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
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MOP080	Latest Progress in Designs and Testings of PIP-II Power Couplers	cavity, rfq, vacuum, multipactoring	263
	S. Kazakov, B.M. Hanna, O.V. Pronitchev, N. Solyak Fermilab, Batavia, Illinois, USA
	Proton Improvement Plan – II (PIP-II) project is under go in Fermi National Laboratory. Main part of the project is 800 MeV proton superconducting accelerator which includes 116 superconducting cavities of 5 different types and three 162.5, 325 and 650 MHz frequencies. Key elements of accelerator which determine a reliable operation are main couplers for superconducting cavities. This paper describes the latest progress in design and testing of main couplers for PIP-II projects.
	Poster MOP080 [0.881 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP080
About •	paper received ※ 18 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
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MOP084	A Simple Variable Coupler for the Cryogenic Test of SRF Cavities	cavity, SRF, coupling, FEL	282
	G. Ciovati, L. Turlington JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The cryogenic rf tests of SRF cavities in vertical cryostats is typically carried out using fixed-length antennae to couple rf power into the cavity and to probe the energy stored into the cavity. Although variable couplers have been designed, built and used in the past, they are often a complex, costly, not very reliable auxiliary component to the cavity test. In this contribution we present the design and implementation of a simple variable rf antenna which has about 50 mm travel, allowing to obtain about four orders of magnitude variation in Q_ext -value. The motion of the antenna is driven by a motorized linear feedthrough outside of the cryostat. The antenna can easily be mounted on the most common type of cavity flanges.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP084
About •	paper received ※ 18 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
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MOP092	Overview of LCLS-II Project Status at Fermilab	cryomodule, SRF, cavity, controls	302
	R.P. Stanek, T.T. Arkan, J.N. Blowers, C.M. Ginsburg, A. Grassellino, C.J. Grimm, B.J. Hansen, E.R. Harms, B.D. Hartsell, J.P. Holzbauer, J.A. Kaluzny, A.L. Klebaner, A. Martinez, T.H. Nicol, Y.O. Orlov, K.S. Premo, N. Solyak, J. Theilacker, G. Wu Fermilab, Batavia, Illinois, USA
	The superconducting RF Continuous-Wave (CW) Linac for the LCLS-II consists of thirty-five 1.3 GHz and two 3.9 GHz cryomodules that Fermilab and Jefferson Lab are jointly producing in collaboration with SLAC. Fermilab¿s scope of work is to build, test, and deliver half the 1.3 GHz and all the 3.9 GHz cryomodules and to design and procure components for the cryogenic distribution system. Fermilab has primary responsibility for delivering a working design. The cryomodule design basis was the European XFEL but several elements evolved to meet CW operation requirements and specifics of the SLAC tunnel. There have been several challenges faced during the design, assembly, testing and transportation of the cryomodules which have required design updates. Success in overcoming these challenges is attributable to the strength of the LCLS-II SRF Collaboration (Fermilab, Jefferson Lab and SLAC with extensive help from DESY and CEA/Saclay). The cryogenic distribution system has progressed relatively well and there are valuable Lessons Learned. An overview of the status, accomplishments, problems encountered, solutions developed, and a summary of Lessons Learned will be presented.
	Poster MOP092 [0.393 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP092
About •	paper received ※ 20 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
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MOP094	Design Strategy of the PIP-II Cryomodules	cryomodule, cavity, vacuum, interface	307
	V. Roger, S.K. Chandrasekaran, D. Passarelli Fermilab, Batavia, Illinois, USA
	Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics The Proton Improvement Plan II (PIP-II) is the first U.S. accelerator project that will have significant contributions from international partners. Research institutions in India, Italy, UK and France will build major components of the particle accelerator. The High Beta 650 MHz (HB650) prototype cryomodule is being designed jointly between Fermilab (USA), CEA (France), STFC (UK) and RRCAT (India). The assembly of this prototype cryomodule will be done at Fermilab whereas the production cryomodules will be assembled in UK. Concerning the Low Beta 650 MHz (LB650) cryomodules, they will be designed and assembled at CEA. To reduce the cost of the project and to increase the quality it is essential to define a design strategy for each cryomodule which includes a degree of standardization. In this way, the lessons learned of each prototype cryomodule will have a great impact not only on one cryomodule type but on all cryomodules. An international joint design brings also additional challenges to the project: which unit system should be used? Should a common project lifecycle management system be used for all partners? How to transport the cryomodules overseas.
	Poster MOP094 [1.117 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP094
About •	paper received ※ 21 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
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MOP098	Spoke Cryomodule Prototyping for the MINERVA Project	cryomodule, cavity, operation, controls	315
	H. Saugnac, S. Blivet, N. Gandolfo, C. Joly, W. Kaabi, J. Lesrel, D. Longuevergne, G. Olivier, M. Pierens, W. Sarlin Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France M.A. Baylac, D. Bondoux, F. Bouly, P.-O. Dumont, Y. Gómez Martínez LPSC, Grenoble Cedex, France
	In the framework of the MINERVA (MYRRHA 100 MeV) project, a prototyping period started at the end of 2017, has been planned. During this period a prototype cryomodule fully equipped (Spoke Cavities, Cryomodule Vessel, Cold Tuning System, Magnetic shielding, Power Couplers¿) as well as its operating and controlling components (LLRF, RF amplifiers¿) will be studied and manufactured. The aim of this prototyping period is first to complete the study of all the components and to validate the manufacturing and the assembling procedure in order to freeze the specifications for the serial construction. On the other hand the prototypes will serve as a test stand allowing to study and adjust the "Fault Tolerance" strategy parameters , which is a challenging operating concept specific to the MYRRHA LINAC This poster presents the various tasks related to this Spoke Cryomodule prototyping and their status.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP098
About •	paper received ※ 23 June 2019 paper accepted ※ 02 July 2019 issue date ※ 14 August 2019
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MOP099	Design of Crab Cavity Cryomodule for HL-LHC	cryomodule, cavity, vacuum, operation	320
	T. Capelli, K. Artoos, A.B. Boucherie, K. Brodzinski, R. Calaga, S.J. Calvo, E. Cano-Pleite, O. Capatina, F. Carra, L. Dassa, F. Eriksson, M. Garlasché, A. Krawczyk, R. Leuxe, P. Minginette, E. Montesinos, B. Prochal, M. Sosin, M. Therasse CERN, Geneva, Switzerland T.J. Jones, N. Templeton STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom A. Krawczyk, B. Prochal IFJ-PAN, Kraków, Poland S.M. Pattalwar STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: Research supported by the HL-LHC project Crab cavities are a key element to achieve the HL-LHC performance goals. There are two types of cavities Double Quarter Wave (DQW) for vertical crabbing, and Radiofrequency Dipole (RFD) for horizontal crabbing. Cavities are hosted in a cryomodule to provide optimal conditions for their operation at 2K while minimizing the external thermal loads and stray magnetic fields. One crab cryomodule contains more than thirteen thousand components and the assembly procedure for the first DQW prototype was carefully planned and executed. It was installed in the SPS accelerator at CERN in 2018 and successfully tested with proton beams. A review has thus been performed right after completion of the assembly in order to gather all the experience acquired and improve accordingly the design of the next generation of crab cryomodules. A second cryomodule with two RFD cavities is currently under production. This paper presents the lessons learnt from the first assembly and their implementation to the design of the future crab cryomodules.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP099
About •	paper received ※ 21 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
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MOP101	Design and Manufacturing Challenges of the SSR1 Current Leads for PIP-II	cryomodule, focusing, vacuum, instrumentation	329
	S. Cheban, D. Passarelli, V. Roger Fermilab, Batavia, Illinois, USA
	The SSR1 cryomodule contains eight 325 MHz superconducting single spoke cavities and four solenoid-based focusing lenses operating at 2 K. The focusing lens for SSR1 cryomodule, is a superconducting magnet surrounded by a helium box which will be filled with liquid helium. The magnet assembly is composed of one solenoid with operating current 70 A and 2 quadrupoles correctors with operating current 45 A. The conduction cooled current leads will be used to power magnets. The details of current leads design, fabrication and room temperature qualification will be presented. Main emphasis will be put on the design and production process challenges and possible solutions to fulfilled operation requirement under low temperature conditions.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP101
About •	paper received ※ 28 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
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TUP012	Evaluation of High Performance Large Grain Medium Purity SRF Cavity From KEK	cavity, niobium, SRF, experiment	415
	P. Dhakal, G. Ciovati, G.R. Myneni JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. We presented the RF measurement on a 1.3 GHz single cell cavity fabricated at KEK using large grain ingot niobium with RRR=10⁷. The cavity reached to 35 MV/m with Q₀ = 2.0×10^zEhNZeHn at 2.0 K, record performance on the cavity made from medium purity ingot niobium. The cavity was cool down with different temperature gradient along the cavity axis in order to understand the flux expulsion mechanism when the cavity does through the superconducting transition and effect of trap residual magnetic field on the residual resistance. The measurement showed the excellent flux expulsion with the flux trapping sensitivity of 0.29 nΩ/mG for electro polished surface and 0.44 nΩ/mG for cavity followed by low temperature baking at 120°C for 12 hours. We acknowledge KEK for sending this cavity for evaluations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP012
About •	paper received ※ 17 June 2019 paper accepted ※ 29 June 2019 issue date ※ 14 August 2019
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TUP034	Microphonics Testing of LCLS II Cryomodules at Jefferson Lab	cavity, cryomodule, background, vacuum	493
	T. Powers, N.C. Brock, G.K. Davis JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 Jefferson Lab is partnering with Fermilab to build the 36 cryomodules for the LCLS II accelerator that will be installed at SLAC. The cavities have design loaded-Q of 4×10⁷, which means that it has a control bandwidth of 16 Hz. The JLab prototype cryomodule was instrumented with a series of seven accelerometers, and impulse hammer response measurements were made while the cryomodule was being built and after it was installed in the JLab cryomodule test facility. This was done so that we could understand the shapes of the modes of the structure. These results were compared to impulse hammer testing from the outside of the cryomodule and to individual cavity frequency shifts when the cryomodule was cold. The prototype cryomodule had excessive microphonics of 150 Hz peak due to a thermos-acoustic oscillation. Design modifications were implemented and subsequently the cryomodules had microphonics on the order of 10 to 20 Hz. Results of the modal analysis as well as the background microphonics observed when operated under various cryogenic conditions and with different modifications will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP034
About •	paper received ※ 21 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019
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TUP050	A Multi-layered SRF Cavity for Conduction Cooling Applications	cavity, SRF, ECR, niobium	538
	G. Ciovati, G. Cheng, E. Daly, G.V. Eremeev, J. Henry, R.A. Rimmer JLab, Newport News, Virginia, USA I.P. Parajuli ODU, Norfolk, Virginia, USA U. Pudasaini The College of William and Mary, Williamsburg, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Some of the work was supported by the 2008 PECASE Award of G. Ciovati. I. Parajuli is supported by NSF Grant PHYS-100614-010 Industrial application of SRF technology would favor the use of cryocoolers to conductively cool SRF cavities for particle accelerators, operating at or above 4.3 K. In order to achieve a lower surface resistance than Nb at 4.3 K, a superconductor with higher critical temperature should be used, whereas a metal with higher thermal conductivity than Nb should be used to conduct the heat to the cryocoolers. A standard 1.5 GHz bulk Nb single-cell cavity has been coated with a ~2 µm thick layer of Nb₃Sn on the inner surface and with a 5 mm thick Cu layer on the outer surface for conduction cooled applications. The cavity performance has been measured at 4.3 K and 2.0 K in liquid He. The cavity reached a peak surface magnetic field of ~40 mT with a quality factor of 6×10⁹ and 3.5×10⁹ at 4.3 K, before and after applying the thick Cu layer, respectively.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP050
About •	paper received ※ 21 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
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TUP052	Design and Commissioning of a Magnetic Field Scanning System for SRF Cavities	cavity, SRF, data-acquisition, experiment	547
	I.P. Parajuli, J.R. Delayen, A.V. Gurevich, J. Nice ODU, Norfolk, Virginia, USA G. Ciovati, W.A. Clemens, J.R. Delayen JLab, Newport News, Virginia, USA
	Funding: Work supported by NSF Grant 100614-010. G. C. is supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Trapped magnetic vortices are one of the leading sources of residual losses in SRF cavities. Mechanisms of flux pinning depend on the materials treatment and cool-down conditions. A magnetic field scanning system using flux-gate magnetometers and Hall probes has been designed and built to allow measuring the local magnetic field of trapped vortices normal to the outer surface of 1.3 GHz single-cell SRF cavities at cryogenic temperatures. Such system will allow inferring the key information about the distribution and magnitude of trapped flux in the SRF cavities for different material, surface preparations and cool-down conditions.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP052
About •	paper received ※ 22 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
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TUP070	The SRF Thin Film Test Facility in LHe-Free Cryostat	cavity, SRF, vacuum, controls	610
	O.B. Malyshev, J.A. Conlon, P. Goudket, N. Pattalwar, S.M. Pattalwar STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom G. Burt Cockcroft Institute, Warrington, Cheshire, United Kingdom G. Burt Lancaster University, Lancaster, United Kingdom
	An ongoing programme of development superconducting thin film coating for SRF cavities requires a facility for a quick sample evaluation at the RF conditions. One of the key specifications is a simplicity of the testing procedure, allowing an easy installation and quick turnover of the testing samples. Choked test cavities operating at 7.8 GHz with three RF chokes have been designed and tested at DL in a LHe cryostat verifying that the system could perform as required. Having a sample and a cavity physically separate reduces the complexity involved in changing samples (major causes of low throughput rate and high running costs for other test cavities) and also allows direct measurement of the RF power dissipated in the sample via power calorimetry. However, changing a sample and preparation for a test requires about two-week effort per sample. In order to simplify the measurements and achieve a faster turnaround, a new cryostat cooled with a closed-cycle refrigerator has been designed, built and tested. Changing a sample, cooling down and testing can be reduced to 2-3 days per sample. Detailed design and results of testing of this facility will be reported at the conference.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP070
About •	paper received ※ 21 June 2019 paper accepted ※ 02 July 2019 issue date ※ 14 August 2019
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THP002	Metallographic Polishing Pathway to the Future of Large Scale SRF Facilities	SRF, cavity, niobium, embedded	828
	O. Hryhorenko, M. Chabot Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France C.Z. Antoine CEA-IRFU, Gif-sur-Yvette, France D. Longuevergne FLUO, Orsay, France
	Funding: The financial support from the European Nuclear Science and Applications Research 2 (ENSAR 2) under grant agreeement N°654002. Optimization of SRF cavities mainly focuses on pushing the limits of bulk Niobium, cost reduction of cavity fabrication and development of new SRF materials for future accelerators (ILC, FCC). Nowadays chemical etching is the only surface treatment used to prepare SRF surface made of Nb. However the operational cost of chemical facilities is high and these present a very bad ecological footprint. The search of an alternative technique could make the construction of these future large scale facilities possible. Metallographic polishing (MP) is a candidate not only for bulk Nb treatment, but could also provide the mirror-finished substrate for alternative SRF thin films deposition. Recent R&D studies, conducted at IPNO & IRFU, focused on the development of 2-steps MP procedure of Nb flat samples. Roughness of polished surface has been proven better than standard EP treatment and less polluted than CBP. MP provides on flat surfaces a high removal rate (above 1 µm/min) and high reproducibility. The paper will describe the optimized method and present all the surface analysis performed. The first RF characterization of a polished disk will be presented.
	Poster THP002 [2.902 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP002
About •	paper received ※ 20 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
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THP027	Cryogenics Performance of the Vertical Cryostat for Qualifying ESS-SRF High Beta Cavities	cavity, SRF, operation, MMI	895
	S.M. Pattalwar, R.K. Buckley, P.C. Hornickel, K.J. Middleman, M.D. Pendleton, P. Pizzol, P.A. Smith, T.M. Weston, A.E. Wheelhouse, S. Wilde STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom A.J. May, A. Oates, J.T.G. Wilson STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	An innovative vertical cryostat has been developed and commissioned at STFC Daresbury Laboratory for qualifying the high-beta SRF cavities for the ESS (European Spallation Source). The cryostat is designed to test 3 dressed cavities in horizontal configuration in one cold run at 2K. The cavities are cooled to 2K with superfluid liquid helium filled into individual helium jackets of the cavities. This reduces the liquid helium consumption by more than 70% in comparison with the conventional vertical tests. The paper describes the cryogenic system and its performance with detail discussions on the initial results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP027
About •	paper received ※ 22 June 2019 paper accepted ※ 03 July 2019 issue date ※ 14 August 2019
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THP033	Cryogenic Systems Studies for the MINERVA 100 MeV Proton SC LINAC Project	linac, cavity, cryomodule, proton	918
	O. Kochebina, F. Dieudegard, T. Junquera Accelerators and Cryogenic Systems, Orsay, France D. Vandeplassche SCK•CEN, Mol, Belgium
	The construction of the first phase of the MYRRHA project (MINERVA: 100 MeV-4 mA proton Linac) was recently decided by the Belgium Government. In the long term, the MYRRHA project plans to construct an ADS demonstrator for the transmutation of long-lived radioactive waste. It will include a subcritical reactor of 100 MW thermal power and a CW proton Linac accelerator (600 MeV-4 mA). The main challenge of this Linac is an extremely high reliability performance to limit stresses and long restart procedures of the reactor. The MINERVA Linac includes 30 cryomodules housing 60 Single-Spoke SC cavities. A cryomodule prototype with its valve box is under construction at IPNO institute. The cavities operate at 352 MHz in a superfluid Helium bath at 2K. Therefore, a reliable SC Linac Cryogenic System is essential. This article presents the preliminary studies in this subject including the analysis of high thermal loads induced by the CW mode operation of cavities (950 W@2 K per cryomodule). A Cryogenic Refrigerator with an equivalent power capacity of 2645 W @4.5 K (3970 W with 1.5 overcapacity factor) is proposed. The constrains for the He distribution in the Linac tunnel are also discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP033
About •	paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
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THP034	The First Tests on Vertical Cryostat GERSEMI at FREIA Facility	controls, operation, MMI, vacuum	921
	J.P. Thermeau Laboratoire APC, Paris, France K.J. Gajewski, L. Hermansson, R.J.M.Y. Ruber, R. Santiago Kern Uppsala University, Uppsala, Sweden T. Junquera, O. Kochebina Accelerators and Cryogenic Systems, Orsay, France
	A new vertical cryostat, called Gersemi, installed at FREIA Laboratory at Uppsala University, Sweden, is designed to test superconducting magnets and radio-frequency cavities and operates at temperatures between 1.8 K and 4.2 K. Two different inserts can be used to test different superconducting equipment: a helium saturated bath insert for cavities without a helium vessel and a λ-plate insert for magnet testing in superfluid helium pressurized bath. The cold vessel cryostat has an internal diameter of 1.1 m and a useful height of 3.5 m. A valve box supplies the cryostat with the cryogens (LN2, LHe, SHe) and is linked to a gas reheater. The last one is connected to a helium recovery circuit and to a helium pumping system (4.5 g/s at 16 mbar). The Gersemi vertical cryostat is a part of FREIA cryogenic facility which also contains a helium liquefier and a horizontal cryostat inside of a bunker allowing the test of superconducting cavity cryomodules. The first results of the cryogenic tests on this equipment are reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP034
About •	paper received ※ 23 June 2019 paper accepted ※ 04 July 2019 issue date ※ 14 August 2019
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THP051	Upgrades to Cryogenic Capabilities for Cryomodule Testing at JLab	cryomodule, cavity, operation, HOM	983
	N.A. Huque, E. Daly, T. Wijeratne JLab, Newport News, Virginia, USA
	The cryogenic facilities for cryomodule testing at Jefferson Lab (JLab) have been modified and to enable testing of Linear Coherent Light Source-II (LCLS-II) cryomodules. Temporary changes in u-tube connections at the Cryogenic Test Facility (CTF) has enabled rates of cavity cooling that are a factor of 10 higher than previously achieved. Cryogenic connections at JLab¿s Low Energy Recirculator Facility (LERF) have been repurposed to enable two LCLS-II cryomodules to be tested in series. This testing shares the helium space with the Central Helium Liquefier (CHL) that is also used by the Continuous Electron Beam Accelerator Facility (CEBAF). Cryomodule testing can occur while beam operation is ongoing at CEBAF. Improvements to these facilities have allowed the testing of the JLab¿s highest ever performing cryomodules.
	Poster THP051 [0.722 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP051
About •	paper received ※ 20 June 2019 paper accepted ※ 29 June 2019 issue date ※ 14 August 2019
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THP054	Cryogenic Installations for Module Tests at Mainz	cryomodule, operation, SRF, cavity	997
	F. Hug, K. Aulenbacher, E. Schilling, D. Simon, T. Stengler, S.D.W. Thomas KPH, Mainz, Germany K. Aulenbacher, T. Kürzeder HIM, Mainz, Germany A. Skora IKP, Mainz, Germany
	Funding: This work is supported by the German Research Foundation (DFG) under the Cluster of Excellence "PRISMA+" EXC 2118/2019 At Helmholtz Institute Mainz a cryomodule test bunker has been set up for testing dressed modules at 2 K. In a first measurement campaign the high power rf tests of two 1.3 GHz cryomodules for the future MESA accelerator have been performed. We will report on the performance of the test setup, the present and upcom-ing cryogenic installations at the Institute for Nuclear Physics at Mainz, and in particular on the Helium re-frigeration and transport system comprising of a 220 m transport line for liquified gases.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP054
About •	paper received ※ 29 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
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THP064	The Cryostat Results of Carbon Contamination and Plasma Cleaning for the Field Emission on the SRF Cavity	cavity, plasma, SRF, experiment	1038
	A.D. Wu, Q.W. Chu, H. Guo, Y. He, S.C. Huang, C.L. Li, F. Pan, Y.K. Song, T. Tan, P.R. Xiong, W.M. Yue, S.H. Zhang, H.W. Zhao IMP/CAS, Lanzhou, People’s Republic of China
	The field emission effect is the mainly limitation for the operating of SRF cavities in higher gradient with stability. In this paper, the experiments were performed to evaluate the impact of the carbon contaminants and plasma cleaning on the performance of SRF cavity. Contamination mechanism was classified into cryogenic adsorption with weak strength and chemical deposition with strong strength. For the weak strength condition, the methane was injected into the SRF cavity during vertical test to make a cryogenic adsorption layer on the inner surface of the cavity. The results revealed that the performance of SRF cavity degraded by methane physical adsorption, but the performance can be recovered by thermal cycle the cavity to 300K and pump methane out. For the strong strength condition, the chemical deposited dirty layer of carbon contamination was produced by using of Ar/CH₄ mixed PECVD method, and the SRF cavity performance was deteriorated by the severe field emission. Finally, carbon deposited cavity was treated by the Ar/O2 plasma, and its results revealed that the field emission removed greatly and the gradient was increased.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP064
About •	paper received ※ 20 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019
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THP068	Evaluation of Low Heat Conductivity RF Cables	vacuum, cavity, insertion, SRF	1045
	G. Cheng, G. Ciovati, M.L. Morrone JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. New potential applications of superconducting radio-frequency can be envisioned with conduction cooling of the cavities using cryocoolers. In this case, the total heat load to the cryocoolers have to be carefully managed to assure sufficient margin to operate the cavity at an acceptable accelerating gradient. The static and dynamic heat load from rf cables connected to the cavity can be a significant contribution to the total heat load. In this contribution we report the results from measurements of the temperature profile at 1.3 GHz for two low heat conductivity rf cables, as a function of the rf power and with one end of the cable in thermal contact with a liquid helium bath at 4.3 K. A parametric model of the two cables was developed with ANSYS to match the temperature profiles and calculate the heat load at the cold end of the cable.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP068
About •	paper received ※ 21 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
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THP087	2 K SUPERFLUID HELIUM CRYOGENIC VERTICAL TEST STAND OF PAPS	cavity, vacuum, superconducting-cavity, SRF	1107
	L.R. Sun, R. Ge, R. Han, Y.C. Jiang, S.P. Li, C.C. Ma, M.J. Sang, M.F. Xu, R. Ye, J.H. Zhang, X.Z. Zhang, Z.Z. Zhang, T.X. Zhao IHEP, Beijing, People’s Republic of China
	Platform of Advanced Photon Source Technology R&D (PAPS) in the Institute of High Energy Physics (IHEP) is an ongoing project, which aimed to provide a comprehensive research and testing platform for the particle accelerator, X-ray detection and optics. As one of the important parts of the platform, cryogenic vertical test stand for the superconducting cavities is composed of three big vertical test cryostats with 2 different inner diameters, which can provide 4.5K liquid helium, 2K superfluid helium and the lowest 1.5K environments according to the cavities test requirements. The cryogen-ic vertical test stands also focus on current international ¿hot spot¿ fast cool down to the superconducting cavi-ties, maximum liquid helium mass flow rate can be reached to 80g/s. Because of the big size of the cryostats and certain scale, the finished cryogenic vertical test stand can meet several different type cavities test, such as 1.3GHz 9cell, Spoke, elliptical, etc. And also can provide the cavities¿ mass vertical testing for the large scale superconducting accelerators.
	Poster THP087 [1.182 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP087
About •	paper received ※ 20 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019
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THP091	Upgrade of the Fermilab Spoke Test Cryostat for Testing of PIP-II 650 MHz 5-Cell Elliptical Cavities	cavity, vacuum, MMI, interface	1124
	A.I. Sukhanov, S.K. Chandrasekaran, B.M. Hanna, T.H. Nicol, J.P. Ozelis, Y.M. Pischalnikov, D. Plant, O.V. Prokofiev, O.V. Pronitchev, V. Roger, W. Schappert, I. Terechkine, V.P. Yakovlev Fermilab, Batavia, Illinois, USA C. Contreras-Martinez FRIB, East Lansing, Michigan, USA
	Design of the high beta 650 MHz prototype cryomodule for PIP-II is currently undergoing at Fermilab. The cryomodule includes six 5-cell elliptical SRF cavities with accelerating voltage up to 20 MV and low heat dissipation (Q₀ > 3·10^zEhNZeHn). Characterization of performance of fully integrated jacketed cavities with high power coupler and tuner is crucial for the project. Such a characterization of jacketed cavity requires a horizontal test cryostat. Existing horizontal testing facilities at Fermilab, Horizontal Test Stand (HTS) and Spoke Test Cryostat (STC), are not large enough to accommodate jacketed 650 MHz 5-cell cavity. An upgrade of the STC is proposed to install extension to the cryostat and modify cryogenic connections and RF infrastructure to provide testing of 650 MHz cavities. In this paper we describe STC upgrade and commissioning of the upgraded facility. We discuss mitigation of issues and problems specific for testing of high Q₀ 650 MHz cavities, which require low residual magnetic field and low acoustic and mechanical vibrations environment.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP091
About •	paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
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THP106	An SRF Test Stand in High Intensity and High Energy Proton Beams	cavity, cryomodule, vacuum, SRF	1187
	G. Vandoni, K. Artoos, V. Baglin, K. Brodzinski, R. Calaga, O. Capatina, S.D. Claudet, L.P. Delprat, S. Mehanneche, E. Montesinos, C. Pasquino, J.S. Swieszek CERN, Meyrin, Switzerland
	In the framework of HL-LHC, a new infrastructure was installed in 2018, to test SRF structures in the proton beams of the SPS. Scope of the test stand is to study the operational performance of crab cavities for HL-LHC – more generally, SRF cavities – through a wide range of proton beam parameters up to high energy and current, under safe conditions for equipment and personnel. The SPS beam instrumentation is used to monitor orbit centering, RF phase scans, bunch rotation. To minimize impact on beam time, infrastructure and services allow for full remote control. Critical aperture restrictions is overcome by placing the test structure and its ancillaries on a motorized table for lateral translation in- and out of beam. Two articulated Y-shaped vacuum chambers connect the test cryomodule on a beam by-pass. A new cryogenic refrigerator is installed in a split scheme, with an underground cold box fed from a surface compressor. The two Inductive Output Tubes (IOT) power amplifiers deliver up to 60 kW cw via coaxial transmission lines to the two cavities and charges and circulators, the latter installed on the translation table. Interlocks and safety equipment complete the test stand.
	Poster THP106 [3.982 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP106
About •	paper received ※ 23 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019
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Paper

Title

Other Keywords

Page

MOFAA3

The FRIB SC-Linac - Installation and Phased Commissioning

cryomodule, MMI, cavity, linac

12

J. Wei, H. Ao, S. Beher, B. Bird, N.K. Bultman, F. Casagrande, D. Chabot, W. Chang, S. Cogan, C. Compton, J. Curtin, K.D. Davidson, E. Daykin, K. Elliott, A. Facco, A. Fila, V. Ganni, A. Ganshyn, P.E. Gibson, T. Glasmacher, I. Grender, W. Hartung, L. Hodges, K. Holland, H.-C. Hseuh, A. Hussain, M. Ikegami, S. Jones, T. Kanemura, S.H. Kim, P. Knudsen, M.G. Konrad, J. LeTourneau, Z. Li, S.M. Lidia, G. Machicoane, P. Manwiller, F. Marti, T. Maruta, E.S. Metzgar, S.J. Miller, D.G. Morris, C. Nguyen, K. Openlander, P.N. Ostroumov, A.S. Plastun, J.T. Popielarski, L. Popielarski, J. Priller, M.A. Reaume, H.T. Ren, T. Russo, K. Saito, M. Shuptar, J.W. Stetson, D.R. Victory, R. Walker, X. Wang, J.D. Wenstrom, M. Wright, M. Xu, T. Xu, Y. Yamazaki, Q. Zhao, S. Zhao
FRIB, East Lansing, Michigan, USA
K. Dixon, M. Wiseman
JLab, Newport News, Virginia, USA
A. Facco
INFN/LNL, Legnaro (PD), Italy
K. Hosoyama
KEK, Ibaraki, Japan
M.P. Kelly
ANL, Lemont, Illinois, USA
R.E. Laxdal
TRIUMF, Vancouver, Canada

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
The Facility for Rare Isotope Beams (FRIB) superconducting (SC) driver linac is designed to accelerate all stable ions including uranium to energies above 200 MeV/u primarily with 46 cryomodules containing 324 quarter-wave resonators (QWR) and half-wave (HWR) resonators. With the newly commissioned helium refrigeration system supplying liquid helium to the QWR and solenoids, heavy ion beams including Ne, Ar, Kr and Xe were accelerated to the charge stripper location above 20 MeV/u with the first linac segment consisting of 15 cryomodules containing 10⁴ QWRs of β=0.041 and 0.085 and 39 solenoids. Installation of cryomodules with β=0.29 and 0.53 HWRs is proceeding in parallel. Development of β=0.65 elliptical resonators is on-going supporting the FRIB energy upgrade to 400 MeV/u. This paper summarizes the SC-linac installation and phased commissioning status that is on schedule and on budget to the FRIB project.

Slides MOFAA3 [46.571 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOFAA3

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paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

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MOP035

Cryogenic Infrastructure at BESSY II – Current Installations and Future Developments

cavity, storage-ring, gun, radiation

131

S. Heling, W. Anders, J. Heinrich, A. Hellwig, K. Janke, S. Rotterdam
HZB, Berlin, Germany

In Berlin-Adlershof the Helmholtz-Zentrum Berlin (HZB) is operating the synchrotron radiation source BESSY II. Two superconducting wave-length shifter magnets are built-in the storage ring of BESSY II which are cooled with liquid helium. Additionally several test facilities for superconducting cavities are operated at HZB needing helium at 1.8 K. The required helium is supplied by two helium liquefiers. Parallel to operation of the existing facilities the BERLinPro project will qualify as test facility for ERL science and technology. In order to guarantee the required supply with helium at different temperature levels one of the existing helium liquefiers has been relocated to the new accelerator building and the existing cryogenic infrastructure has been upgraded with a new 10 000 L dewar, three valve boxes, a cold compressor box, warm pumps and a 80 K helium system. This paper specifies the setup of the above described helium cryoplants in detail and gives insight into the challenges of development. The paper concludes with an outlook of the upcoming developments of the cryogenic infrastructure at HZB.

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP035

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paper received ※ 20 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

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MOP076

Fundamental Power Coupler Design for a 325 MHz Balloon SSR Cavity

cavity, multipactoring, vacuum, simulation

252

R.E. Laxdal, Y. Ma, B. Matheson, B.S. Waraich, Z.Y. Yao, V. Zvyagintsev
TRIUMF, Vancouver, Canada

TRIUMF has designed, fabricated and tested the first balloon variant of the single spoke resonator at 325 MHz and β=0.3. TRIUMF has also designed a 6 kW fundamental power coupler as part of the development. The design of the coupler will be presented.

Poster MOP076 [1.282 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP076

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paper received ※ 24 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

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MOP080

Latest Progress in Designs and Testings of PIP-II Power Couplers

cavity, rfq, vacuum, multipactoring

263

S. Kazakov, B.M. Hanna, O.V. Pronitchev, N. Solyak
Fermilab, Batavia, Illinois, USA

Proton Improvement Plan – II (PIP-II) project is under go in Fermi National Laboratory. Main part of the project is 800 MeV proton superconducting accelerator which includes 116 superconducting cavities of 5 different types and three 162.5, 325 and 650 MHz frequencies. Key elements of accelerator which determine a reliable operation are main couplers for superconducting cavities. This paper describes the latest progress in design and testing of main couplers for PIP-II projects.

Poster MOP080 [0.881 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP080

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paper received ※ 18 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

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MOP084

A Simple Variable Coupler for the Cryogenic Test of SRF Cavities

cavity, SRF, coupling, FEL

282

G. Ciovati, L. Turlington
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The cryogenic rf tests of SRF cavities in vertical cryostats is typically carried out using fixed-length antennae to couple rf power into the cavity and to probe the energy stored into the cavity. Although variable couplers have been designed, built and used in the past, they are often a complex, costly, not very reliable auxiliary component to the cavity test. In this contribution we present the design and implementation of a simple variable rf antenna which has about 50 mm travel, allowing to obtain about four orders of magnitude variation in Q_ext -value. The motion of the antenna is driven by a motorized linear feedthrough outside of the cryostat. The antenna can easily be mounted on the most common type of cavity flanges.

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP084

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paper received ※ 18 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

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MOP092

Overview of LCLS-II Project Status at Fermilab

cryomodule, SRF, cavity, controls

302

R.P. Stanek, T.T. Arkan, J.N. Blowers, C.M. Ginsburg, A. Grassellino, C.J. Grimm, B.J. Hansen, E.R. Harms, B.D. Hartsell, J.P. Holzbauer, J.A. Kaluzny, A.L. Klebaner, A. Martinez, T.H. Nicol, Y.O. Orlov, K.S. Premo, N. Solyak, J. Theilacker, G. Wu
Fermilab, Batavia, Illinois, USA

The superconducting RF Continuous-Wave (CW) Linac for the LCLS-II consists of thirty-five 1.3 GHz and two 3.9 GHz cryomodules that Fermilab and Jefferson Lab are jointly producing in collaboration with SLAC. Fermilab¿s scope of work is to build, test, and deliver half the 1.3 GHz and all the 3.9 GHz cryomodules and to design and procure components for the cryogenic distribution system. Fermilab has primary responsibility for delivering a working design. The cryomodule design basis was the European XFEL but several elements evolved to meet CW operation requirements and specifics of the SLAC tunnel. There have been several challenges faced during the design, assembly, testing and transportation of the cryomodules which have required design updates. Success in overcoming these challenges is attributable to the strength of the LCLS-II SRF Collaboration (Fermilab, Jefferson Lab and SLAC with extensive help from DESY and CEA/Saclay). The cryogenic distribution system has progressed relatively well and there are valuable Lessons Learned. An overview of the status, accomplishments, problems encountered, solutions developed, and a summary of Lessons Learned will be presented.

Poster MOP092 [0.393 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP092

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paper received ※ 20 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

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MOP094

Design Strategy of the PIP-II Cryomodules

cryomodule, cavity, vacuum, interface

307

V. Roger, S.K. Chandrasekaran, D. Passarelli
Fermilab, Batavia, Illinois, USA

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics
The Proton Improvement Plan II (PIP-II) is the first U.S. accelerator project that will have significant contributions from international partners. Research institutions in India, Italy, UK and France will build major components of the particle accelerator. The High Beta 650 MHz (HB650) prototype cryomodule is being designed jointly between Fermilab (USA), CEA (France), STFC (UK) and RRCAT (India). The assembly of this prototype cryomodule will be done at Fermilab whereas the production cryomodules will be assembled in UK. Concerning the Low Beta 650 MHz (LB650) cryomodules, they will be designed and assembled at CEA. To reduce the cost of the project and to increase the quality it is essential to define a design strategy for each cryomodule which includes a degree of standardization. In this way, the lessons learned of each prototype cryomodule will have a great impact not only on one cryomodule type but on all cryomodules. An international joint design brings also additional challenges to the project: which unit system should be used? Should a common project lifecycle management system be used for all partners? How to transport the cryomodules overseas.

Poster MOP094 [1.117 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP094

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paper received ※ 21 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

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MOP098

Spoke Cryomodule Prototyping for the MINERVA Project

cryomodule, cavity, operation, controls

315

H. Saugnac, S. Blivet, N. Gandolfo, C. Joly, W. Kaabi, J. Lesrel, D. Longuevergne, G. Olivier, M. Pierens, W. Sarlin
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
M.A. Baylac, D. Bondoux, F. Bouly, P.-O. Dumont, Y. Gómez Martínez
LPSC, Grenoble Cedex, France

In the framework of the MINERVA (MYRRHA 100 MeV) project, a prototyping period started at the end of 2017, has been planned. During this period a prototype cryomodule fully equipped (Spoke Cavities, Cryomodule Vessel, Cold Tuning System, Magnetic shielding, Power Couplers¿) as well as its operating and controlling components (LLRF, RF amplifiers¿) will be studied and manufactured. The aim of this prototyping period is first to complete the study of all the components and to validate the manufacturing and the assembling procedure in order to freeze the specifications for the serial construction. On the other hand the prototypes will serve as a test stand allowing to study and adjust the "Fault Tolerance" strategy parameters , which is a challenging operating concept specific to the MYRRHA LINAC This poster presents the various tasks related to this Spoke Cryomodule prototyping and their status.

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP098

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paper received ※ 23 June 2019 paper accepted ※ 02 July 2019 issue date ※ 14 August 2019

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MOP099

Design of Crab Cavity Cryomodule for HL-LHC

cryomodule, cavity, vacuum, operation

320

T. Capelli, K. Artoos, A.B. Boucherie, K. Brodzinski, R. Calaga, S.J. Calvo, E. Cano-Pleite, O. Capatina, F. Carra, L. Dassa, F. Eriksson, M. Garlasché, A. Krawczyk, R. Leuxe, P. Minginette, E. Montesinos, B. Prochal, M. Sosin, M. Therasse
CERN, Geneva, Switzerland
T.J. Jones, N. Templeton
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
A. Krawczyk, B. Prochal
IFJ-PAN, Kraków, Poland
S.M. Pattalwar
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: Research supported by the HL-LHC project
Crab cavities are a key element to achieve the HL-LHC performance goals. There are two types of cavities Double Quarter Wave (DQW) for vertical crabbing, and Radiofrequency Dipole (RFD) for horizontal crabbing. Cavities are hosted in a cryomodule to provide optimal conditions for their operation at 2K while minimizing the external thermal loads and stray magnetic fields. One crab cryomodule contains more than thirteen thousand components and the assembly procedure for the first DQW prototype was carefully planned and executed. It was installed in the SPS accelerator at CERN in 2018 and successfully tested with proton beams. A review has thus been performed right after completion of the assembly in order to gather all the experience acquired and improve accordingly the design of the next generation of crab cryomodules. A second cryomodule with two RFD cavities is currently under production. This paper presents the lessons learnt from the first assembly and their implementation to the design of the future crab cryomodules.

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP099

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paper received ※ 21 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

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MOP101

Design and Manufacturing Challenges of the SSR1 Current Leads for PIP-II

cryomodule, focusing, vacuum, instrumentation

329

S. Cheban, D. Passarelli, V. Roger
Fermilab, Batavia, Illinois, USA

The SSR1 cryomodule contains eight 325 MHz superconducting single spoke cavities and four solenoid-based focusing lenses operating at 2 K. The focusing lens for SSR1 cryomodule, is a superconducting magnet surrounded by a helium box which will be filled with liquid helium. The magnet assembly is composed of one solenoid with operating current 70 A and 2 quadrupoles correctors with operating current 45 A. The conduction cooled current leads will be used to power magnets. The details of current leads design, fabrication and room temperature qualification will be presented. Main emphasis will be put on the design and production process challenges and possible solutions to fulfilled operation requirement under low temperature conditions.

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP101

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paper received ※ 28 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

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TUP012

Evaluation of High Performance Large Grain Medium Purity SRF Cavity From KEK

cavity, niobium, SRF, experiment

415

P. Dhakal, G. Ciovati, G.R. Myneni
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
We presented the RF measurement on a 1.3 GHz single cell cavity fabricated at KEK using large grain ingot niobium with RRR=10⁷. The cavity reached to 35 MV/m with Q₀ = 2.0×10^zEhNZeHn at 2.0 K, record performance on the cavity made from medium purity ingot niobium. The cavity was cool down with different temperature gradient along the cavity axis in order to understand the flux expulsion mechanism when the cavity does through the superconducting transition and effect of trap residual magnetic field on the residual resistance. The measurement showed the excellent flux expulsion with the flux trapping sensitivity of 0.29 nΩ/mG for electro polished surface and 0.44 nΩ/mG for cavity followed by low temperature baking at 120°C for 12 hours.
We acknowledge KEK for sending this cavity for evaluations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP012

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paper received ※ 17 June 2019 paper accepted ※ 29 June 2019 issue date ※ 14 August 2019

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TUP034

Microphonics Testing of LCLS II Cryomodules at Jefferson Lab

cavity, cryomodule, background, vacuum

493

T. Powers, N.C. Brock, G.K. Davis
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
Jefferson Lab is partnering with Fermilab to build the 36 cryomodules for the LCLS II accelerator that will be installed at SLAC. The cavities have design loaded-Q of 4×10⁷, which means that it has a control bandwidth of 16 Hz. The JLab prototype cryomodule was instrumented with a series of seven accelerometers, and impulse hammer response measurements were made while the cryomodule was being built and after it was installed in the JLab cryomodule test facility. This was done so that we could understand the shapes of the modes of the structure. These results were compared to impulse hammer testing from the outside of the cryomodule and to individual cavity frequency shifts when the cryomodule was cold. The prototype cryomodule had excessive microphonics of 150 Hz peak due to a thermos-acoustic oscillation. Design modifications were implemented and subsequently the cryomodules had microphonics on the order of 10 to 20 Hz. Results of the modal analysis as well as the background microphonics observed when operated under various cryogenic conditions and with different modifications will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP034

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paper received ※ 21 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019

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TUP050

A Multi-layered SRF Cavity for Conduction Cooling Applications

cavity, SRF, ECR, niobium

538

G. Ciovati, G. Cheng, E. Daly, G.V. Eremeev, J. Henry, R.A. Rimmer
JLab, Newport News, Virginia, USA
I.P. Parajuli
ODU, Norfolk, Virginia, USA
U. Pudasaini
The College of William and Mary, Williamsburg, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Some of the work was supported by the 2008 PECASE Award of G. Ciovati. I. Parajuli is supported by NSF Grant PHYS-100614-010
Industrial application of SRF technology would favor the use of cryocoolers to conductively cool SRF cavities for particle accelerators, operating at or above 4.3 K. In order to achieve a lower surface resistance than Nb at 4.3 K, a superconductor with higher critical temperature should be used, whereas a metal with higher thermal conductivity than Nb should be used to conduct the heat to the cryocoolers. A standard 1.5 GHz bulk Nb single-cell cavity has been coated with a ~2 µm thick layer of Nb₃Sn on the inner surface and with a 5 mm thick Cu layer on the outer surface for conduction cooled applications. The cavity performance has been measured at 4.3 K and 2.0 K in liquid He. The cavity reached a peak surface magnetic field of ~40 mT with a quality factor of 6×10⁹ and 3.5×10⁹ at 4.3 K, before and after applying the thick Cu layer, respectively.

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP050

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paper received ※ 21 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

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TUP052

Design and Commissioning of a Magnetic Field Scanning System for SRF Cavities

cavity, SRF, data-acquisition, experiment

547

I.P. Parajuli, J.R. Delayen, A.V. Gurevich, J. Nice
ODU, Norfolk, Virginia, USA
G. Ciovati, W.A. Clemens, J.R. Delayen
JLab, Newport News, Virginia, USA

Funding: Work supported by NSF Grant 100614-010. G. C. is supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Trapped magnetic vortices are one of the leading sources of residual losses in SRF cavities. Mechanisms of flux pinning depend on the materials treatment and cool-down conditions. A magnetic field scanning system using flux-gate magnetometers and Hall probes has been designed and built to allow measuring the local magnetic field of trapped vortices normal to the outer surface of 1.3 GHz single-cell SRF cavities at cryogenic temperatures. Such system will allow inferring the key information about the distribution and magnitude of trapped flux in the SRF cavities for different material, surface preparations and cool-down conditions.

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP052

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paper received ※ 22 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

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TUP070

The SRF Thin Film Test Facility in LHe-Free Cryostat

cavity, SRF, vacuum, controls

610

O.B. Malyshev, J.A. Conlon, P. Goudket, N. Pattalwar, S.M. Pattalwar
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
G. Burt
Cockcroft Institute, Warrington, Cheshire, United Kingdom
G. Burt
Lancaster University, Lancaster, United Kingdom

An ongoing programme of development superconducting thin film coating for SRF cavities requires a facility for a quick sample evaluation at the RF conditions. One of the key specifications is a simplicity of the testing procedure, allowing an easy installation and quick turnover of the testing samples. Choked test cavities operating at 7.8 GHz with three RF chokes have been designed and tested at DL in a LHe cryostat verifying that the system could perform as required. Having a sample and a cavity physically separate reduces the complexity involved in changing samples (major causes of low throughput rate and high running costs for other test cavities) and also allows direct measurement of the RF power dissipated in the sample via power calorimetry. However, changing a sample and preparation for a test requires about two-week effort per sample. In order to simplify the measurements and achieve a faster turnaround, a new cryostat cooled with a closed-cycle refrigerator has been designed, built and tested. Changing a sample, cooling down and testing can be reduced to 2-3 days per sample. Detailed design and results of testing of this facility will be reported at the conference.

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP070

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paper received ※ 21 June 2019 paper accepted ※ 02 July 2019 issue date ※ 14 August 2019

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THP002

Metallographic Polishing Pathway to the Future of Large Scale SRF Facilities

SRF, cavity, niobium, embedded

828

O. Hryhorenko, M. Chabot
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
C.Z. Antoine
CEA-IRFU, Gif-sur-Yvette, France
D. Longuevergne
FLUO, Orsay, France

Funding: The financial support from the European Nuclear Science and Applications Research 2 (ENSAR 2) under grant agreeement N°654002.
Optimization of SRF cavities mainly focuses on pushing the limits of bulk Niobium, cost reduction of cavity fabrication and development of new SRF materials for future accelerators (ILC, FCC). Nowadays chemical etching is the only surface treatment used to prepare SRF surface made of Nb. However the operational cost of chemical facilities is high and these present a very bad ecological footprint. The search of an alternative technique could make the construction of these future large scale facilities possible. Metallographic polishing (MP) is a candidate not only for bulk Nb treatment, but could also provide the mirror-finished substrate for alternative SRF thin films deposition. Recent R&D studies, conducted at IPNO & IRFU, focused on the development of 2-steps MP procedure of Nb flat samples. Roughness of polished surface has been proven better than standard EP treatment and less polluted than CBP. MP provides on flat surfaces a high removal rate (above 1 µm/min) and high reproducibility. The paper will describe the optimized method and present all the surface analysis performed. The first RF characterization of a polished disk will be presented.

Poster THP002 [2.902 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP002

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paper received ※ 20 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

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THP027

Cryogenics Performance of the Vertical Cryostat for Qualifying ESS-SRF High Beta Cavities

cavity, SRF, operation, MMI

895

S.M. Pattalwar, R.K. Buckley, P.C. Hornickel, K.J. Middleman, M.D. Pendleton, P. Pizzol, P.A. Smith, T.M. Weston, A.E. Wheelhouse, S. Wilde
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
A.J. May, A. Oates, J.T.G. Wilson
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

An innovative vertical cryostat has been developed and commissioned at STFC Daresbury Laboratory for qualifying the high-beta SRF cavities for the ESS (European Spallation Source). The cryostat is designed to test 3 dressed cavities in horizontal configuration in one cold run at 2K. The cavities are cooled to 2K with superfluid liquid helium filled into individual helium jackets of the cavities. This reduces the liquid helium consumption by more than 70% in comparison with the conventional vertical tests. The paper describes the cryogenic system and its performance with detail discussions on the initial results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP027

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paper received ※ 22 June 2019 paper accepted ※ 03 July 2019 issue date ※ 14 August 2019

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THP033

Cryogenic Systems Studies for the MINERVA 100 MeV Proton SC LINAC Project

linac, cavity, cryomodule, proton

918

O. Kochebina, F. Dieudegard, T. Junquera
Accelerators and Cryogenic Systems, Orsay, France
D. Vandeplassche
SCK•CEN, Mol, Belgium

The construction of the first phase of the MYRRHA project (MINERVA: 100 MeV-4 mA proton Linac) was recently decided by the Belgium Government. In the long term, the MYRRHA project plans to construct an ADS demonstrator for the transmutation of long-lived radioactive waste. It will include a subcritical reactor of 100 MW thermal power and a CW proton Linac accelerator (600 MeV-4 mA). The main challenge of this Linac is an extremely high reliability performance to limit stresses and long restart procedures of the reactor. The MINERVA Linac includes 30 cryomodules housing 60 Single-Spoke SC cavities. A cryomodule prototype with its valve box is under construction at IPNO institute. The cavities operate at 352 MHz in a superfluid Helium bath at 2K. Therefore, a reliable SC Linac Cryogenic System is essential. This article presents the preliminary studies in this subject including the analysis of high thermal loads induced by the CW mode operation of cavities (950 W@2 K per cryomodule). A Cryogenic Refrigerator with an equivalent power capacity of 2645 W @4.5 K (3970 W with 1.5 overcapacity factor) is proposed. The constrains for the He distribution in the Linac tunnel are also discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP033

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paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

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THP034

The First Tests on Vertical Cryostat GERSEMI at FREIA Facility

controls, operation, MMI, vacuum

921

J.P. Thermeau
Laboratoire APC, Paris, France
K.J. Gajewski, L. Hermansson, R.J.M.Y. Ruber, R. Santiago Kern
Uppsala University, Uppsala, Sweden
T. Junquera, O. Kochebina
Accelerators and Cryogenic Systems, Orsay, France

A new vertical cryostat, called Gersemi, installed at FREIA Laboratory at Uppsala University, Sweden, is designed to test superconducting magnets and radio-frequency cavities and operates at temperatures between 1.8 K and 4.2 K. Two different inserts can be used to test different superconducting equipment: a helium saturated bath insert for cavities without a helium vessel and a λ-plate insert for magnet testing in superfluid helium pressurized bath. The cold vessel cryostat has an internal diameter of 1.1 m and a useful height of 3.5 m. A valve box supplies the cryostat with the cryogens (LN2, LHe, SHe) and is linked to a gas reheater. The last one is connected to a helium recovery circuit and to a helium pumping system (4.5 g/s at 16 mbar). The Gersemi vertical cryostat is a part of FREIA cryogenic facility which also contains a helium liquefier and a horizontal cryostat inside of a bunker allowing the test of superconducting cavity cryomodules. The first results of the cryogenic tests on this equipment are reported.

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP034

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paper received ※ 23 June 2019 paper accepted ※ 04 July 2019 issue date ※ 14 August 2019

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THP051

Upgrades to Cryogenic Capabilities for Cryomodule Testing at JLab

cryomodule, cavity, operation, HOM

983

N.A. Huque, E. Daly, T. Wijeratne
JLab, Newport News, Virginia, USA

The cryogenic facilities for cryomodule testing at Jefferson Lab (JLab) have been modified and to enable testing of Linear Coherent Light Source-II (LCLS-II) cryomodules. Temporary changes in u-tube connections at the Cryogenic Test Facility (CTF) has enabled rates of cavity cooling that are a factor of 10 higher than previously achieved. Cryogenic connections at JLab¿s Low Energy Recirculator Facility (LERF) have been repurposed to enable two LCLS-II cryomodules to be tested in series. This testing shares the helium space with the Central Helium Liquefier (CHL) that is also used by the Continuous Electron Beam Accelerator Facility (CEBAF). Cryomodule testing can occur while beam operation is ongoing at CEBAF. Improvements to these facilities have allowed the testing of the JLab¿s highest ever performing cryomodules.

Poster THP051 [0.722 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP051

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paper received ※ 20 June 2019 paper accepted ※ 29 June 2019 issue date ※ 14 August 2019

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THP054

Cryogenic Installations for Module Tests at Mainz

cryomodule, operation, SRF, cavity

997

F. Hug, K. Aulenbacher, E. Schilling, D. Simon, T. Stengler, S.D.W. Thomas
KPH, Mainz, Germany
K. Aulenbacher, T. Kürzeder
HIM, Mainz, Germany
A. Skora
IKP, Mainz, Germany

Funding: This work is supported by the German Research Foundation (DFG) under the Cluster of Excellence "PRISMA+" EXC 2118/2019
At Helmholtz Institute Mainz a cryomodule test bunker has been set up for testing dressed modules at 2 K. In a first measurement campaign the high power rf tests of two 1.3 GHz cryomodules for the future MESA accelerator have been performed. We will report on the performance of the test setup, the present and upcom-ing cryogenic installations at the Institute for Nuclear Physics at Mainz, and in particular on the Helium re-frigeration and transport system comprising of a 220 m transport line for liquified gases.

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP054

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paper received ※ 29 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

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THP064

The Cryostat Results of Carbon Contamination and Plasma Cleaning for the Field Emission on the SRF Cavity

cavity, plasma, SRF, experiment

1038

A.D. Wu, Q.W. Chu, H. Guo, Y. He, S.C. Huang, C.L. Li, F. Pan, Y.K. Song, T. Tan, P.R. Xiong, W.M. Yue, S.H. Zhang, H.W. Zhao
IMP/CAS, Lanzhou, People’s Republic of China

The field emission effect is the mainly limitation for the operating of SRF cavities in higher gradient with stability. In this paper, the experiments were performed to evaluate the impact of the carbon contaminants and plasma cleaning on the performance of SRF cavity. Contamination mechanism was classified into cryogenic adsorption with weak strength and chemical deposition with strong strength. For the weak strength condition, the methane was injected into the SRF cavity during vertical test to make a cryogenic adsorption layer on the inner surface of the cavity. The results revealed that the performance of SRF cavity degraded by methane physical adsorption, but the performance can be recovered by thermal cycle the cavity to 300K and pump methane out. For the strong strength condition, the chemical deposited dirty layer of carbon contamination was produced by using of Ar/CH₄ mixed PECVD method, and the SRF cavity performance was deteriorated by the severe field emission. Finally, carbon deposited cavity was treated by the Ar/O2 plasma, and its results revealed that the field emission removed greatly and the gradient was increased.

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP064

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paper received ※ 20 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019

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THP068

Evaluation of Low Heat Conductivity RF Cables

vacuum, cavity, insertion, SRF

1045

G. Cheng, G. Ciovati, M.L. Morrone
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
New potential applications of superconducting radio-frequency can be envisioned with conduction cooling of the cavities using cryocoolers. In this case, the total heat load to the cryocoolers have to be carefully managed to assure sufficient margin to operate the cavity at an acceptable accelerating gradient. The static and dynamic heat load from rf cables connected to the cavity can be a significant contribution to the total heat load. In this contribution we report the results from measurements of the temperature profile at 1.3 GHz for two low heat conductivity rf cables, as a function of the rf power and with one end of the cable in thermal contact with a liquid helium bath at 4.3 K. A parametric model of the two cables was developed with ANSYS to match the temperature profiles and calculate the heat load at the cold end of the cable.

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP068

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paper received ※ 21 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

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THP087

2 K SUPERFLUID HELIUM CRYOGENIC VERTICAL TEST STAND OF PAPS

cavity, vacuum, superconducting-cavity, SRF

1107

L.R. Sun, R. Ge, R. Han, Y.C. Jiang, S.P. Li, C.C. Ma, M.J. Sang, M.F. Xu, R. Ye, J.H. Zhang, X.Z. Zhang, Z.Z. Zhang, T.X. Zhao
IHEP, Beijing, People’s Republic of China

Platform of Advanced Photon Source Technology R&D (PAPS) in the Institute of High Energy Physics (IHEP) is an ongoing project, which aimed to provide a comprehensive research and testing platform for the particle accelerator, X-ray detection and optics. As one of the important parts of the platform, cryogenic vertical test stand for the superconducting cavities is composed of three big vertical test cryostats with 2 different inner diameters, which can provide 4.5K liquid helium, 2K superfluid helium and the lowest 1.5K environments according to the cavities test requirements. The cryogen-ic vertical test stands also focus on current international ¿hot spot¿ fast cool down to the superconducting cavi-ties, maximum liquid helium mass flow rate can be reached to 80g/s. Because of the big size of the cryostats and certain scale, the finished cryogenic vertical test stand can meet several different type cavities test, such as 1.3GHz 9cell, Spoke, elliptical, etc. And also can provide the cavities¿ mass vertical testing for the large scale superconducting accelerators.

Poster THP087 [1.182 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP087

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paper received ※ 20 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019

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THP091

Upgrade of the Fermilab Spoke Test Cryostat for Testing of PIP-II 650 MHz 5-Cell Elliptical Cavities

cavity, vacuum, MMI, interface

1124

A.I. Sukhanov, S.K. Chandrasekaran, B.M. Hanna, T.H. Nicol, J.P. Ozelis, Y.M. Pischalnikov, D. Plant, O.V. Prokofiev, O.V. Pronitchev, V. Roger, W. Schappert, I. Terechkine, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA
C. Contreras-Martinez
FRIB, East Lansing, Michigan, USA

Design of the high beta 650 MHz prototype cryomodule for PIP-II is currently undergoing at Fermilab. The cryomodule includes six 5-cell elliptical SRF cavities with accelerating voltage up to 20 MV and low heat dissipation (Q₀ > 3·10^zEhNZeHn). Characterization of performance of fully integrated jacketed cavities with high power coupler and tuner is crucial for the project. Such a characterization of jacketed cavity requires a horizontal test cryostat. Existing horizontal testing facilities at Fermilab, Horizontal Test Stand (HTS) and Spoke Test Cryostat (STC), are not large enough to accommodate jacketed 650 MHz 5-cell cavity. An upgrade of the STC is proposed to install extension to the cryostat and modify cryogenic connections and RF infrastructure to provide testing of 650 MHz cavities. In this paper we describe STC upgrade and commissioning of the upgraded facility. We discuss mitigation of issues and problems specific for testing of high Q₀ 650 MHz cavities, which require low residual magnetic field and low acoustic and mechanical vibrations environment.

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP091

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paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

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THP106

An SRF Test Stand in High Intensity and High Energy Proton Beams

cavity, cryomodule, vacuum, SRF

1187

G. Vandoni, K. Artoos, V. Baglin, K. Brodzinski, R. Calaga, O. Capatina, S.D. Claudet, L.P. Delprat, S. Mehanneche, E. Montesinos, C. Pasquino, J.S. Swieszek
CERN, Meyrin, Switzerland

In the framework of HL-LHC, a new infrastructure was installed in 2018, to test SRF structures in the proton beams of the SPS. Scope of the test stand is to study the operational performance of crab cavities for HL-LHC – more generally, SRF cavities – through a wide range of proton beam parameters up to high energy and current, under safe conditions for equipment and personnel. The SPS beam instrumentation is used to monitor orbit centering, RF phase scans, bunch rotation. To minimize impact on beam time, infrastructure and services allow for full remote control. Critical aperture restrictions is overcome by placing the test structure and its ancillaries on a motorized table for lateral translation in- and out of beam. Two articulated Y-shaped vacuum chambers connect the test cryomodule on a beam by-pass. A new cryogenic refrigerator is installed in a split scheme, with an underground cold box fed from a surface compressor. The two Inductive Output Tubes (IOT) power amplifiers deliver up to 60 kW cw via coaxial transmission lines to the two cavities and charges and circulators, the latter installed on the translation table. Interlocks and safety equipment complete the test stand.

Poster THP106 [3.982 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP106

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paper received ※ 23 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019

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