SRF2023 - List of Keywords (MMI)

Paper	Title	Other Keywords	Page
MOIAA03	Progresses in the ESS Superconducting Linac Installation	cryomodule, linac, operation, cryogenics	9
	H. Przybilski ESS, Lund, Sweden
	The ESS Linac is progressing into the technical commissioning phase. The normal conducting linac up to the first 4 tanks of the DTL is being commissioned with beam. All the 13 spoke cryomodules and the 9 elliptical modules (7 MB+2 HB) foreseen for the first operation at 570 MeV on the beam dump in summer 2024 are available in Lund and waiting the completion of the cryogenic distribution system (CDS) commissioning. The test program of all the 30 elliptical cryomodules that will enable the 5 MW potential operation after the target commissioning is progressing well, as well as the installation of the RF power stations necessary up to the 2 MW stage of the first project phase. Pilot installation of one spoke and one elliptical CM in the tunnel is in progress. The talk will cover the status of the component deliveries from the partners, the CM preparation and SRF activities at the ESS test stands, with the resolution of several non-conformities, and the experience of the pilot installations and technical commissioning activities in the accelerator tunnel.
	Slides MOIAA03 [9.000 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOIAA03
About •	Received ※ 26 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 13 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB026	Development of Transformative Cavity Processing - Superiority of Electropolishing on High Gradient Performance over Buffered Chemical Polishing at Low Frequency (322 MHz)	cavity, SRF, operation, cryomodule	145
	K. Saito, C. Compton, K. Elliott, W. Hartung, S.H. Kim, T.K. Konomi, E.S. Metzgar, S.J. Miller, L. Popielarski, A.T. Taylor, T. Xu FRIB, East Lansing, Michigan, USA
	Funding: The work is supported by DOE Awards DE-SC0022994. A DOE grant R&D titled ¿Development of Transformative Preparation Technology to Push up High Q/G Performance of FRIB Spare HWR Cryomodule Cavities¿ is ongoing at FRIB. This R&D is for 2 years since September 2022. This project proposes four objectives: 1) Superiority on high gradient performance of electropolishing (EP) over buffered chemical polishing at low frequency (322 MHz), 2) High Qo performance by the local magnetic shield, 3) Development of HFQS-free BCP and, 4) Wet N-doping method. This paper will report the result of first object, and a local magnetic shield design and simulation to reduce the residual magnetic field < 0.1 mG in the vertical test Dewar, for the object 2.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB026
About •	Received ※ 14 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 08 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB047	Commissioning of Dedicated Furnace for Nb₃Sn Coatings of 2.6 GHz Single Cell Cavities	cavity, niobium, SRF, factory	216
	P.A. Kulyavtsev, G.V. Eremeev, S. Posen, B. Tennis Fermilab, Batavia, Illinois, USA J. Zasadzinski IIT, Chicago, 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. We present the results of commissioning a dedicated furnace for Nb₃Sn coatings of 2.6GHz single cell cavities. Nb₃Sn is a desired coating due to its high critical temperature and smaller surface resistance compared to bulk Nb. Usage of Nb₃Sn coated cavities will greatly reduce operating costs due to its higher operating temperature providing decreased cooling costs. Tin is deposited in the bulk Nb cavity by use of a tin chloride nucleation agent and tin vapor diffusion. Analysis of the resultant coating was performed using SEM/EDS to verify successful formation of desired Nb:Sn phase. Witness samples located in line of sight of the source were analyzed in order to understand the coating efficacy. The cavity’s performance was assessed in the Vertical Test Stand (VTS) at Fermilab.
	Poster MOPMB047 [4.858 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB047
About •	Received ※ 26 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 08 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB056	Saraf-Phase II: Test of the SRF Cavities with the First Cryomodule	cavity, cryomodule, target, LLRF	238
	G. Ferrand, S. Berry, D. Darde, G. Desmarchelier, F. Hassane, T.J. Joannem, S. Monnereau, N. Pichoff, O. Piquet, Th. Plaisant CEA-IRFU, Gif-sur-Yvette, France
	CEA is committed to delivering a Medium Energy Beam Transfer line and a superconducting linac (SCL) for SARAF accelerator in order to accelerate 5 mA beam of either protons from 1.3 MeV to 35 MeV or deuterons from 2.6 MeV to 40 MeV. The SCL consists in four cryomodules. The first cryomodule hosts 6 half-wave resonator (HWR) low beta cavities (β = 0.09) at 176 MHz. The low-beta cavities were qualified in 2021, as well as the power couplers and frequency tuners. The Low-Level RF (LLRF) system was qualified in 2022 with a dedicated test stand. This contribution will present the results of the RF tests of the first SARAF cryomodule at Saclay.
	Poster MOPMB056 [1.437 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB056
About •	Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 14 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB089	Installation of LCLS-II Cryomodules	cryomodule, vacuum, hardware, cavity	324
	D.A. White, S. Aderhold, R. Coy, D. Gonnella SLAC, Menlo Park, California, USA
	Funding: U.S. Department of Energy The Linac Coherent Light Source II (LCLS-II) super-conducting accelerator is fully installed and operational. Cryomodules were designed and manufactured by Fermi National Accelerator Laboratory (FNAL) and Thomas Jefferson National Laboratory (JLab) during 2017-2020. From November 2018 through March 2021, SLAC Na-tional Accelerator Laboratory installed 37 Cryomodules. Full system cooldown was completed in March 2022. Installation processes were optimized at SLAC for best quality, especially during particle-free and UHV assem-bly. These processes and successful Cavity and Cry-omodule manufacturing resulted in installed gradient exceeding design requirements by more than 20%. No statistical variation in field emission onsets or magni-tudes were observed between manufacturing and site testing. This paper summarizes SLAC experience during installation, and relevant testing results.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB089
About •	Received ※ 20 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 15 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB090	Measuring Q₀ in LCLS-II Cryomodules Using Helium Liquid Level	cavity, cryomodule, linac, SRF	327
	L.M. Zacarias, S. Aderhold, D. Gonnella, J.T. Maniscalco, J. Nelson, R.D. Porter SLAC, Menlo Park, California, USA A.T. Cravatta, J.P. Holzbauer, S. Posen Fermilab, Batavia, Illinois, USA M.A. Drury, M.D. McCaughan, C.M. Wilson JLab, Newport News, Virginia, USA
	The nitrogen-doped cavities used in the Linac Coherent Light Source II (LCLS-II) cryomodules have shown an unprecedented high Q₀ in vertical and cryomodule testing compared with cavities prepared with standard methods. While demonstration of high Q₀ in the test stand has been achieved, maintaining that performance in the linac is critical to the success of LCLS-II and future accelerator projects. The LCLS-II cryomodules required a novel method of measuring Q₀, due to hardware incompatibilities with existing procedures. Initially developed at Jefferson Lab during cryomodule acceptance testing before being used in the tunnel at SLAC, we use helium liquid level data to estimate the heat generated by cavities. We first establish the relationship between the rate of helium evaporation from known heat loads using electric heaters, and then use that relationship to determine heat from an RF load. Here we present the full procedure along with the development process, lessons learned, and reproducibility while demonstrating for the first time that world record Q₀ can be maintained within the real accelerator environment.
	Poster MOPMB090 [1.867 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB090
About •	Received ※ 20 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 13 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB013	Commissioning of a New Sample Test Cavity for Rapid RF Characterization of SRF Materials	cavity, niobium, SRF, operation	410
	S. Keckert, J. Knobloch, F. Kramer, O. Kugeler HZB, Berlin, Germany J. Knobloch University of Siegen, Siegen, Germany
	RaSTA, the Rapid Superconductor Test Apparatus, is a new sample test cavity that is currently being commissioned at HZB. It uses the established QPR sample geometry but with a much smaller cylindrical cavity operating in the TM020 mode at 4.8 GHz. Its compact design allows for smaller cryogenic test stands and reduced turnaround time, enabling iterative measurement campaigns for thin film R&D. Using the same calorimetric measurement technique as known from the QPR allows direct measurements of the residual resistance. We report first prototype results obtained from a niobium sample that demonstrate the capabilities of the system.
	Poster TUPTB013 [0.464 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB013
About •	Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 28 June 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB016	Summary of the FRIB Electropolishing Facility Design and Commissioning, Cavity Processing, and Cavity Test Results	cavity, cathode, power-supply, controls	419
	E.S. Metzgar, B.W. Barker, K. Elliott, J.D. Hulbert, C. Knowles, L. Nguyen, A.R. Nunham, L. Popielarski, A.T. Taylor, T. Xu FRIB, East Lansing, Michigan, USA
	Funding: U.S. Department of Energy, Office of Science, Office of Nuclear Physics and used resources of the FRIB, which is a DOE Office of Science User Facility, under Award Number DE-SC0000661. Recently, a new Electropolishing (EP) facility was con-structed and commissioned at the Facility for Rare Isotope Beam (FRIB) with the purpose of supporting advanced surface processing techniques for SRF R&D activities. The FRIB production cavities opted for a Buffered Chemical Polish (BCP) method due to its cost effectiveness and was supported by successful outcomes in other facilities with low beta cavities in a similar frequency range. All 324 cavities used in FRIB Linac were processed in-house at MSU using BCP and exhibited satisfactory performance during testing. As part of the FRIB energy upgrade R&D, 5-cell 644 MHz elliptical resonators will be employed, desiring the use of EP and advanced techniques such as nitrogen doping and medium-T baking. The EP facility is designed to accommodate all types of cavities used in FRIB and possesses the capability for performing EP at low temperatures. Here we report the details of design and commissioning of the EP facility, highlights of encountered issues and subsequent improvements, and preliminary results from vertical tests conducted on the cavities.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB016
About •	Received ※ 15 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 14 July 2023
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TUPTB019	First Results from Nb₃Sn Coatings of 2.6 GHz Nb SRF Cavities Using DC Cylindrical Magnetron Sputtering System	cavity, SRF, site, vacuum	429
	M.S. Shakel, H. Elsayed-Ali ODU, Norfolk, Virginia, USA G.V. Eremeev Fermilab, Batavia, Illinois, USA U. Pudasaini, A-M. Valente-Feliciano JLab, Newport News, Virginia, USA
	Funding: Supported by DOE, Office of Accelerator R&D and Production, Contact No. DE-SC0022284, with partial support by DOE, Office of Nuclear Physics DE-AC05-06OR23177, Early Career Award to G. Eremeev. A DC cylindrical magnetron sputtering system has been commissioned and operated to deposit Nb₃Sn onto 2.6 GHz Nb SRF cavities. After optimizing the deposition conditions in a mock-up cavity, Nb-Sn films are deposited first on flat samples by multilayer sequential sputtering of Nb and Sn, and later annealed at 950 °C for 3 hours. X-ray diffraction of the films showed multiple peaks for the Nb₃Sn phase and Nb (substrate). No peaks from any Nb-Sn compound other than Nb₃Sn were detected. Later three 2.6 GHz Nb SRF cavities are coated with ~1 µm thick Nb₃Sn. The first Nb₃Sn coated cavity reached close to E_acc = 8 MV/m, demonstrating a quality factor Q₀ of 3.2 × 10⁸ at Tbath = 4.4 K and E_acc = 5 MV/m, about a factor of three higher than that of Nb at this temperature. Q₀ was close to 1.1 × 10⁹, dominated by the residual resistance, at 2 K and E_acc = 5 MV/m. The Nb₃Sn coated cavities demonstrated Tc in the range of 17.9 ¿ 18 K. Here we present the commissioning experience, system optimization, and the first results from the Nb₃Sn fabrication on flat samples and SRF cavities.
	Poster TUPTB019 [1.216 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB019
About •	Received ※ 16 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 10 July 2023
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TUPTB024	Cobotisation of ESS Cryomodule Assembly at CEA	cavity, operation, cryomodule, SRF	438
	S. Berry, A. Bouygues, J. Drant, C. Madec CEA-DRF-IRFU, France A. Gonzalez-Moreau, C. Servouin CEA-IRFU, Gif-sur-Yvette, France
	The assembly of cavity string in the clean room is a tedious work that has noisy and painful steps such as cleaning the taped holes of a part. CEA together with the company INGELIANCE has developed a cobot: a collaborative robot operated by an technician one time and repeating the action without the operator. The cobot can work anytime without any operators : therefore it is working at night reducing the assembly duration by some hours. The cobot consists of a FANUC CRX10 a 6-axis arm on an Arvis cart. At CEA, the cobot is used to blow the flange holes of the cavities and bellows. This allows to reduce the noisy steps that the technicians are exposed to. The process is also more reproducible since the cobot does always the same steps. The cobot is used on ESS cavity string to clean the coupler and cavity flanges. Our activities and results will be presented in this poster.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB024
About •	Received ※ 18 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 03 July 2023
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TUPTB062	RF Measurements of the 3rd Harmonic Superconducting Cavity for a Bunch Lengthening	cavity, niobium, target, superconducting-cavity	565
	J.Y. Yoon, J.H. Han, H.S. Park, Y.D. Yoon Kiswire Advanced Technology Ltd., Daejeon, Republic of Korea E. Kako KEK, Ibaraki, Japan E.-S. Kim Korea University Sejong Campus, Sejong, Republic of Korea
	The brightness can be increased by minimizing the emittance in the light source, but the reduced emittance also increases the number of collisions of electrons in the beam bunch. Therefore, the bunch lengthening by using the 3rd harmonic cavity reduces the collisions of electrons and increases the Touschek lifetime. Since the resonant frequency of the main RF cavity is 500 MHz, the resonant frequency of 3rd harmonic cavity is selected as 1500 MHz. The prototype cavity is a passive type in which a power coupler is not used, and power is supplied from the beam. The operating temperature is 4.5 K, which is a superconducting cavity. The elliptical double-cell geometry was selected to increase the accelerating voltage of the cavity and reduce power losses. Based on this design, three niobium cavities are fabricated and tested. In this paper, we present the RF measurement results of the 3rd harmonic cavity at room temperature. 3rd harmonic cavity 4th generation storage ring
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB062
About •	Received ※ 12 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 13 July 2023
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TUPTB067	Fabrication and Surface Treatment of Superconducting Rf Single Spoke Cavities for the Myrrha Project	cavity, niobium, simulation, linac	578
	M. Moretti, Y.N. Hoerstensmeyer, A. Navitski RI Research Instruments GmbH, Bergisch Gladbach, Germany F. Marhauser SCK•CEN, Mol, Belgium
	The MYRRHA project, based at SCK•CEN (Belgium), aims at coupling a 600 MeV proton accelerator to a subcritical fission core with a maximal output of 100 MWth. The first phase of the project, MINERVA, includes the design, construction, and commissioning of a 100 MeV superconducting RF linac in order to demonstrate the machine requirements in terms of reliability and fault tolerance. The MINERVA linac comprises several cryomodules, each containing two Single Spoke 352.2 MHz cavities made out of high RRR niobium and operating at 2K. The fabrication and surface treatment of the Single Spoke RF Cavities is currently ongoing and completely carried out by RI Research Instruments GmbH (Germany); the first pre-series cavities were completed and delivered for cold testing. Main highlights of the fabrication include the deep-drawing of complex shapes, such as central spokes and outer caps of the cavity, which was successfully accomplished. As for the surface treatment, RI has commissioned, tested, and effectively started utilizing a new rotational buffered chemical polishing facility; this is required to polish the cavity inner surface, while ensuring an almost uniform material removal.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB067
About •	Received ※ 17 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 09 July 2023
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WEPWB043	Nb₃Sn Vapor Diffusion Coating System at SARI: Design, Construction, and Commissioning	cavity, vacuum, niobium, superconducting-cavity	655
	Q.X. Chen, Y. Zong SINAP, Shanghai, People’s Republic of China J.F. Chen, S. Xing SARI-CAS, Pudong, Shanghai, People’s Republic of China J. Rong SSRF, Shanghai, People’s Republic of China
	This paper describes the design of a coating system for the preparation of a superconducting radio-frequency cavity with Nb₃Sn thin films. The device consists of a coating chamber made of pure niobium, a vacuum furnace for heating the coating chamber, a superconducting cavity bracket and two crucible heaters. The chamber is vacuum isolated from the furnace body to protect the superconducting cavity from contamination during the coating process. The device has been built and commissioned, which could be used for Nb₃Sn coating of a 1.3 GHz single-cell superconducting cavity in future.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB043
About •	Received ※ 19 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 08 July 2023
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WEPWB092	Test-Stand for Conditioning of Fundamental Power Couplers at DESY	FEL, vacuum, GUI, cavity	797
	K. Kasprzak, Th. Buettner, A. Gössel, D. Klinke, D. Kostin, C. Müller, E. Vogel, M. Wiencek DESY, Hamburg, Germany
	During the construction of the European-XFEL, activities related to Fundamental Power Couplers (FPCs) were outsourced to external partners and the former FPC test-stand area at DESY was given up due to infrastructure rearrangements. For the study of various XFEL upgrade scenarios a new test-stand for conditioning of FPCs at DESY is required. It will be used for evaluation of new coupler preparation methods with particular emphasis on Continuous Wave (CW) and long RF pulse operation. The new test-stand has been recently commissioned. Four FPCs have been prepared and tested. RF pulses were applied to the couplers, starting with the shortest possible pulse and increasing it’s power until maximum power was reached. The process was repeated with several pulse lengths until the maximum RF pulse length was reached. A review of the commissioning and first operation experience of the RF system are presented here.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB092
About •	Received ※ 15 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 16 July 2023
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Paper

Title

Other Keywords

Page

MOIAA03

Progresses in the ESS Superconducting Linac Installation

cryomodule, linac, operation, cryogenics

9

H. Przybilski
ESS, Lund, Sweden

The ESS Linac is progressing into the technical commissioning phase. The normal conducting linac up to the first 4 tanks of the DTL is being commissioned with beam. All the 13 spoke cryomodules and the 9 elliptical modules (7 MB+2 HB) foreseen for the first operation at 570 MeV on the beam dump in summer 2024 are available in Lund and waiting the completion of the cryogenic distribution system (CDS) commissioning. The test program of all the 30 elliptical cryomodules that will enable the 5 MW potential operation after the target commissioning is progressing well, as well as the installation of the RF power stations necessary up to the 2 MW stage of the first project phase. Pilot installation of one spoke and one elliptical CM in the tunnel is in progress. The talk will cover the status of the component deliveries from the partners, the CM preparation and SRF activities at the ESS test stands, with the resolution of several non-conformities, and the experience of the pilot installations and technical commissioning activities in the accelerator tunnel.

Slides MOIAA03 [9.000 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOIAA03

About •

Received ※ 26 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 13 July 2023

Cite •

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

MOPMB026

Development of Transformative Cavity Processing - Superiority of Electropolishing on High Gradient Performance over Buffered Chemical Polishing at Low Frequency (322 MHz)

cavity, SRF, operation, cryomodule

145

K. Saito, C. Compton, K. Elliott, W. Hartung, S.H. Kim, T.K. Konomi, E.S. Metzgar, S.J. Miller, L. Popielarski, A.T. Taylor, T. Xu
FRIB, East Lansing, Michigan, USA

Funding: The work is supported by DOE Awards DE-SC0022994.
A DOE grant R&D titled ¿Development of Transformative Preparation Technology to Push up High Q/G Performance of FRIB Spare HWR Cryomodule Cavities¿ is ongoing at FRIB. This R&D is for 2 years since September 2022. This project proposes four objectives: 1) Superiority on high gradient performance of electropolishing (EP) over buffered chemical polishing at low frequency (322 MHz), 2) High Qo performance by the local magnetic shield, 3) Development of HFQS-free BCP and, 4) Wet N-doping method. This paper will report the result of first object, and a local magnetic shield design and simulation to reduce the residual magnetic field < 0.1 mG in the vertical test Dewar, for the object 2.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB026

About •

Received ※ 14 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 08 July 2023

Cite •

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

MOPMB047

Commissioning of Dedicated Furnace for Nb₃Sn Coatings of 2.6 GHz Single Cell Cavities

cavity, niobium, SRF, factory

216

P.A. Kulyavtsev, G.V. Eremeev, S. Posen, B. Tennis
Fermilab, Batavia, Illinois, USA
J. Zasadzinski
IIT, Chicago, 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.
We present the results of commissioning a dedicated furnace for Nb₃Sn coatings of 2.6GHz single cell cavities. Nb₃Sn is a desired coating due to its high critical temperature and smaller surface resistance compared to bulk Nb. Usage of Nb₃Sn coated cavities will greatly reduce operating costs due to its higher operating temperature providing decreased cooling costs. Tin is deposited in the bulk Nb cavity by use of a tin chloride nucleation agent and tin vapor diffusion. Analysis of the resultant coating was performed using SEM/EDS to verify successful formation of desired Nb:Sn phase. Witness samples located in line of sight of the source were analyzed in order to understand the coating efficacy. The cavity’s performance was assessed in the Vertical Test Stand (VTS) at Fermilab.

Poster MOPMB047 [4.858 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB047

About •

Received ※ 26 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 08 July 2023

Cite •

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

MOPMB056

Saraf-Phase II: Test of the SRF Cavities with the First Cryomodule

cavity, cryomodule, target, LLRF

238

G. Ferrand, S. Berry, D. Darde, G. Desmarchelier, F. Hassane, T.J. Joannem, S. Monnereau, N. Pichoff, O. Piquet, Th. Plaisant
CEA-IRFU, Gif-sur-Yvette, France

CEA is committed to delivering a Medium Energy Beam Transfer line and a superconducting linac (SCL) for SARAF accelerator in order to accelerate 5 mA beam of either protons from 1.3 MeV to 35 MeV or deuterons from 2.6 MeV to 40 MeV. The SCL consists in four cryomodules. The first cryomodule hosts 6 half-wave resonator (HWR) low beta cavities (β = 0.09) at 176 MHz. The low-beta cavities were qualified in 2021, as well as the power couplers and frequency tuners. The Low-Level RF (LLRF) system was qualified in 2022 with a dedicated test stand. This contribution will present the results of the RF tests of the first SARAF cryomodule at Saclay.

Poster MOPMB056 [1.437 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB056

About •

Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 14 July 2023

Cite •

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

MOPMB089

Installation of LCLS-II Cryomodules

cryomodule, vacuum, hardware, cavity

324

D.A. White, S. Aderhold, R. Coy, D. Gonnella
SLAC, Menlo Park, California, USA

Funding: U.S. Department of Energy
The Linac Coherent Light Source II (LCLS-II) super-conducting accelerator is fully installed and operational. Cryomodules were designed and manufactured by Fermi National Accelerator Laboratory (FNAL) and Thomas Jefferson National Laboratory (JLab) during 2017-2020. From November 2018 through March 2021, SLAC Na-tional Accelerator Laboratory installed 37 Cryomodules. Full system cooldown was completed in March 2022. Installation processes were optimized at SLAC for best quality, especially during particle-free and UHV assem-bly. These processes and successful Cavity and Cry-omodule manufacturing resulted in installed gradient exceeding design requirements by more than 20%. No statistical variation in field emission onsets or magni-tudes were observed between manufacturing and site testing. This paper summarizes SLAC experience during installation, and relevant testing results.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB089

About •

Received ※ 20 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 15 July 2023

Cite •

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

MOPMB090

Measuring Q₀ in LCLS-II Cryomodules Using Helium Liquid Level

cavity, cryomodule, linac, SRF

327

L.M. Zacarias, S. Aderhold, D. Gonnella, J.T. Maniscalco, J. Nelson, R.D. Porter
SLAC, Menlo Park, California, USA
A.T. Cravatta, J.P. Holzbauer, S. Posen
Fermilab, Batavia, Illinois, USA
M.A. Drury, M.D. McCaughan, C.M. Wilson
JLab, Newport News, Virginia, USA

The nitrogen-doped cavities used in the Linac Coherent Light Source II (LCLS-II) cryomodules have shown an unprecedented high Q₀ in vertical and cryomodule testing compared with cavities prepared with standard methods. While demonstration of high Q₀ in the test stand has been achieved, maintaining that performance in the linac is critical to the success of LCLS-II and future accelerator projects. The LCLS-II cryomodules required a novel method of measuring Q₀, due to hardware incompatibilities with existing procedures. Initially developed at Jefferson Lab during cryomodule acceptance testing before being used in the tunnel at SLAC, we use helium liquid level data to estimate the heat generated by cavities. We first establish the relationship between the rate of helium evaporation from known heat loads using electric heaters, and then use that relationship to determine heat from an RF load. Here we present the full procedure along with the development process, lessons learned, and reproducibility while demonstrating for the first time that world record Q₀ can be maintained within the real accelerator environment.

Poster MOPMB090 [1.867 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB090

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Received ※ 20 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 13 July 2023

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TUPTB013

Commissioning of a New Sample Test Cavity for Rapid RF Characterization of SRF Materials

cavity, niobium, SRF, operation

410

S. Keckert, J. Knobloch, F. Kramer, O. Kugeler
HZB, Berlin, Germany
J. Knobloch
University of Siegen, Siegen, Germany

RaSTA, the Rapid Superconductor Test Apparatus, is a new sample test cavity that is currently being commissioned at HZB. It uses the established QPR sample geometry but with a much smaller cylindrical cavity operating in the TM020 mode at 4.8 GHz. Its compact design allows for smaller cryogenic test stands and reduced turnaround time, enabling iterative measurement campaigns for thin film R&D. Using the same calorimetric measurement technique as known from the QPR allows direct measurements of the residual resistance. We report first prototype results obtained from a niobium sample that demonstrate the capabilities of the system.

Poster TUPTB013 [0.464 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB013

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Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 28 June 2023

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TUPTB016

Summary of the FRIB Electropolishing Facility Design and Commissioning, Cavity Processing, and Cavity Test Results

cavity, cathode, power-supply, controls

419

E.S. Metzgar, B.W. Barker, K. Elliott, J.D. Hulbert, C. Knowles, L. Nguyen, A.R. Nunham, L. Popielarski, A.T. Taylor, T. Xu
FRIB, East Lansing, Michigan, USA

Funding: U.S. Department of Energy, Office of Science, Office of Nuclear Physics and used resources of the FRIB, which is a DOE Office of Science User Facility, under Award Number DE-SC0000661.
Recently, a new Electropolishing (EP) facility was con-structed and commissioned at the Facility for Rare Isotope Beam (FRIB) with the purpose of supporting advanced surface processing techniques for SRF R&D activities. The FRIB production cavities opted for a Buffered Chemical Polish (BCP) method due to its cost effectiveness and was supported by successful outcomes in other facilities with low beta cavities in a similar frequency range. All 324 cavities used in FRIB Linac were processed in-house at MSU using BCP and exhibited satisfactory performance during testing. As part of the FRIB energy upgrade R&D, 5-cell 644 MHz elliptical resonators will be employed, desiring the use of EP and advanced techniques such as nitrogen doping and medium-T baking. The EP facility is designed to accommodate all types of cavities used in FRIB and possesses the capability for performing EP at low temperatures. Here we report the details of design and commissioning of the EP facility, highlights of encountered issues and subsequent improvements, and preliminary results from vertical tests conducted on the cavities.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB016

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Received ※ 15 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 14 July 2023

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TUPTB019

First Results from Nb₃Sn Coatings of 2.6 GHz Nb SRF Cavities Using DC Cylindrical Magnetron Sputtering System

cavity, SRF, site, vacuum

429

M.S. Shakel, H. Elsayed-Ali
ODU, Norfolk, Virginia, USA
G.V. Eremeev
Fermilab, Batavia, Illinois, USA
U. Pudasaini, A-M. Valente-Feliciano
JLab, Newport News, Virginia, USA

Funding: Supported by DOE, Office of Accelerator R&D and Production, Contact No. DE-SC0022284, with partial support by DOE, Office of Nuclear Physics DE-AC05-06OR23177, Early Career Award to G. Eremeev.
A DC cylindrical magnetron sputtering system has been commissioned and operated to deposit Nb₃Sn onto 2.6 GHz Nb SRF cavities. After optimizing the deposition conditions in a mock-up cavity, Nb-Sn films are deposited first on flat samples by multilayer sequential sputtering of Nb and Sn, and later annealed at 950 °C for 3 hours. X-ray diffraction of the films showed multiple peaks for the Nb₃Sn phase and Nb (substrate). No peaks from any Nb-Sn compound other than Nb₃Sn were detected. Later three 2.6 GHz Nb SRF cavities are coated with ~1 µm thick Nb₃Sn. The first Nb₃Sn coated cavity reached close to E_acc = 8 MV/m, demonstrating a quality factor Q₀ of 3.2 × 10⁸ at Tbath = 4.4 K and E_acc = 5 MV/m, about a factor of three higher than that of Nb at this temperature. Q₀ was close to 1.1 × 10⁹, dominated by the residual resistance, at 2 K and E_acc = 5 MV/m. The Nb₃Sn coated cavities demonstrated Tc in the range of 17.9 ¿ 18 K. Here we present the commissioning experience, system optimization, and the first results from the Nb₃Sn fabrication on flat samples and SRF cavities.

Poster TUPTB019 [1.216 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB019

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Received ※ 16 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 10 July 2023

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TUPTB024

Cobotisation of ESS Cryomodule Assembly at CEA

cavity, operation, cryomodule, SRF

438

S. Berry, A. Bouygues, J. Drant, C. Madec
CEA-DRF-IRFU, France
A. Gonzalez-Moreau, C. Servouin
CEA-IRFU, Gif-sur-Yvette, France

The assembly of cavity string in the clean room is a tedious work that has noisy and painful steps such as cleaning the taped holes of a part. CEA together with the company INGELIANCE has developed a cobot: a collaborative robot operated by an technician one time and repeating the action without the operator. The cobot can work anytime without any operators : therefore it is working at night reducing the assembly duration by some hours. The cobot consists of a FANUC CRX10 a 6-axis arm on an Arvis cart. At CEA, the cobot is used to blow the flange holes of the cavities and bellows. This allows to reduce the noisy steps that the technicians are exposed to. The process is also more reproducible since the cobot does always the same steps. The cobot is used on ESS cavity string to clean the coupler and cavity flanges. Our activities and results will be presented in this poster.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB024

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Received ※ 18 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 03 July 2023

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TUPTB062

RF Measurements of the 3rd Harmonic Superconducting Cavity for a Bunch Lengthening

cavity, niobium, target, superconducting-cavity

565

J.Y. Yoon, J.H. Han, H.S. Park, Y.D. Yoon
Kiswire Advanced Technology Ltd., Daejeon, Republic of Korea
E. Kako
KEK, Ibaraki, Japan
E.-S. Kim
Korea University Sejong Campus, Sejong, Republic of Korea

The brightness can be increased by minimizing the emittance in the light source, but the reduced emittance also increases the number of collisions of electrons in the beam bunch. Therefore, the bunch lengthening by using the 3rd harmonic cavity reduces the collisions of electrons and increases the Touschek lifetime. Since the resonant frequency of the main RF cavity is 500 MHz, the resonant frequency of 3rd harmonic cavity is selected as 1500 MHz. The prototype cavity is a passive type in which a power coupler is not used, and power is supplied from the beam. The operating temperature is 4.5 K, which is a superconducting cavity. The elliptical double-cell geometry was selected to increase the accelerating voltage of the cavity and reduce power losses. Based on this design, three niobium cavities are fabricated and tested. In this paper, we present the RF measurement results of the 3rd harmonic cavity at room temperature.
*3rd harmonic cavity
*4th generation storage ring

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB062

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Received ※ 12 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 13 July 2023

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TUPTB067

Fabrication and Surface Treatment of Superconducting Rf Single Spoke Cavities for the Myrrha Project

cavity, niobium, simulation, linac

578

M. Moretti, Y.N. Hoerstensmeyer, A. Navitski
RI Research Instruments GmbH, Bergisch Gladbach, Germany
F. Marhauser
SCK•CEN, Mol, Belgium

The MYRRHA project, based at SCK•CEN (Belgium), aims at coupling a 600 MeV proton accelerator to a subcritical fission core with a maximal output of 100 MWth. The first phase of the project, MINERVA, includes the design, construction, and commissioning of a 100 MeV superconducting RF linac in order to demonstrate the machine requirements in terms of reliability and fault tolerance. The MINERVA linac comprises several cryomodules, each containing two Single Spoke 352.2 MHz cavities made out of high RRR niobium and operating at 2K. The fabrication and surface treatment of the Single Spoke RF Cavities is currently ongoing and completely carried out by RI Research Instruments GmbH (Germany); the first pre-series cavities were completed and delivered for cold testing. Main highlights of the fabrication include the deep-drawing of complex shapes, such as central spokes and outer caps of the cavity, which was successfully accomplished. As for the surface treatment, RI has commissioned, tested, and effectively started utilizing a new rotational buffered chemical polishing facility; this is required to polish the cavity inner surface, while ensuring an almost uniform material removal.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB067

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Received ※ 17 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 09 July 2023

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WEPWB043

Nb₃Sn Vapor Diffusion Coating System at SARI: Design, Construction, and Commissioning

cavity, vacuum, niobium, superconducting-cavity

655

Q.X. Chen, Y. Zong
SINAP, Shanghai, People’s Republic of China
J.F. Chen, S. Xing
SARI-CAS, Pudong, Shanghai, People’s Republic of China
J. Rong
SSRF, Shanghai, People’s Republic of China

This paper describes the design of a coating system for the preparation of a superconducting radio-frequency cavity with Nb₃Sn thin films. The device consists of a coating chamber made of pure niobium, a vacuum furnace for heating the coating chamber, a superconducting cavity bracket and two crucible heaters. The chamber is vacuum isolated from the furnace body to protect the superconducting cavity from contamination during the coating process. The device has been built and commissioned, which could be used for Nb₃Sn coating of a 1.3 GHz single-cell superconducting cavity in future.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB043

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Received ※ 19 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 08 July 2023

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WEPWB092

Test-Stand for Conditioning of Fundamental Power Couplers at DESY

FEL, vacuum, GUI, cavity

797

K. Kasprzak, Th. Buettner, A. Gössel, D. Klinke, D. Kostin, C. Müller, E. Vogel, M. Wiencek
DESY, Hamburg, Germany

During the construction of the European-XFEL, activities related to Fundamental Power Couplers (FPCs) were outsourced to external partners and the former FPC test-stand area at DESY was given up due to infrastructure rearrangements. For the study of various XFEL upgrade scenarios a new test-stand for conditioning of FPCs at DESY is required. It will be used for evaluation of new coupler preparation methods with particular emphasis on Continuous Wave (CW) and long RF pulse operation. The new test-stand has been recently commissioned. Four FPCs have been prepared and tested. RF pulses were applied to the couplers, starting with the shortest possible pulse and increasing it’s power until maximum power was reached. The process was repeated with several pulse lengths until the maximum RF pulse length was reached. A review of the commissioning and first operation experience of the RF system are presented here.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB092

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Received ※ 15 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 16 July 2023

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