SRF2023 - List of Keywords (cryogenics)

Paper	Title	Other Keywords	Page
MOIAA03	Progresses in the ESS Superconducting Linac Installation	cryomodule, linac, MMI, operation	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)

MOPMB010	Analysis of Semiconductor Components as Temperature Sensors for Cryogenic Investigation of SRF Materials	cavity, controls, experiment, SRF	80
	A. Cierpka, S. Keckert, J. Knobloch, F. Kramer, O. Kugeler HZB, Berlin, Germany
	Temperature mapping systems have been used for many years to detect local heating in an SRF cavity surface or materials sample. They require a large number of temperature sensors. Most often, low-cost Allen-Bradley resistors are used for this purpose. Since they have poor sensitivity and reproducibility above 4 K, sensor alternatives that combine the precision of Cernox sensors with the low-cost of Allen-Bradley resistors would be highly desirable. In this work various semiconductor components that exhibit a temperature dependent electrical response, such as diodes and LEDs were analyzed with respect to sensitivity, reproducibility and response speed in a temperature range between 6.5 K and 22 K. In this range, many diodes and LEDs were found to be more sensitive than Cernox sensors. However, in some components the response time was slow - possibly due to poor thermal contact.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB010
About •	Received ※ 08 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 17 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB014	NbTi Thin Film SRF Cavities for Dark Matter Search	cavity, target, SRF, photon	96
	G. Marconato Università degli Studi di Padova, Padova, Italy D. Alesini, A. D’Elia, D. Di Gioacchino, C. Gatti, C. Ligi, G. Maccarrone, A. Rettaroli, S. Tocci LNF-INFN, Frascati, Italy O. Azzolini, R. Caforio, E. Chyhyrynets, D. Fonnesu, D. Ford, V.A. Garcia, G. Keppel, C. Pira, A. Salmaso, F. Stivanello INFN/LNL, Legnaro (PD), Italy C. Braggio Univ. degli Studi di Padova, Padova, Italy D. D’Agostino, U. Gambardella INFN-Salerno, Baronissi, Salerno, Italy S. Posen Fermilab, Batavia, Illinois, USA
	Funding: Resources from U.S. DOE, Ofce of Science, NQISRC, SQMS contract No DE-AC02-07CH11359. Also from EU’s Horizon 2020 Research and Innovation programme, Grant Agreement No 101004730; INFN CSNV exp. SAMARA The search for dark matter is now looking at ALPs (axion-like particles) as a very promising candidate to understand our universe. Within this framework, we explore the possibility to use NbTi thin film coatings on Cu resonating cavities to investigate the presence of axions in the range of 35-45 µeV mass by coupling the axion to a very strong magnetic field inside the cavity, causing its conversion to a photon which is subsequently detected. In this work the chemical treatments and DC magnetron sputtering details of the preparation of 9 GHz, 7 GHz, and 3.9 GHz resonant cavities and their quality factor measurements at different applied magnetic fields are presented.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB014
About •	Received ※ 18 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 26 July 2023
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MOPMB017	Development of a Thermal Conductance Instrument for Niobium at Cryogenic Temperatures	cavity, niobium, ECR, operation	109
	C. Saribal, C. Martens University of Hamburg, Hamburg, Germany W. Hillert, M. Wenskat University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	Funding: University of Hamburg Particle accelerators form an important tool in a variety of research fields. In an effort to reduce operation costs while maintaining high energies, their accelerating structures are steadily improved towards higher accelerating fields and lower RF losses. Stable operation of such a cavity generally requires Joule-heating, generated in its walls, to be conducted to an outer helium bath. Therefore, it is of interest to experimentally evaluate how present and future cavity treatments affect thermal characteristics. We present an instrument for measuring the thermal performance of SRF cavity materials at cryogenic temperatures. Pairs of niobium disks are placed inside of a liquid helium bath and a temperature gradient is generated across them to obtain total thermal resistance for temperatures below 2 Kelvin. To get an idea of the instruments sensitivity and how standard cavity treatments influence thermal resistance, samples are tested post fabrication, polishing and 800 °C baking. The first tests show the commissioning of our newly set up system and if it is feasible to observe relevant changes and evaluate new and promising cavity treatments such as SIS structures.
	Poster MOPMB017 [3.217 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB017
About •	Received ※ 17 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 01 July 2023
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MOPMB036	Magnetic Field Mapping of a Large-Grain 1.3 GHz Single-Cell Cavity	cavity, radio-frequency, niobium, SRF	172
	I.P. Parajuli, J.R. Delayen, A.V. Gurevich ODU, Norfolk, Virginia, USA G. Ciovati JLab, Newport News, Virginia, USA
	Funding: This work was supported by the National Science Foundation under Grant No. PHY 100614-010. G.C. is supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. A new magnetic field mapping system for 1.3 GHz single-cell cavities was developed in order to reveal the impact of ambient magnetic field and temperature gradients during cool-down on the flux trapping phenomenon. Measurements were done at 2 K for different cool-down conditions of a large-grain cavity before and after 120 °C bake. The fraction of applied magnetic field trapped in the cavity walls was ~ 50% after slow cool-down and ~20% after fast cool-down. The results showed a weak correlation between between trapped flux locations and hot-spots causing the high-field Q-slope. The results also showed an increase of the trapped flux at the quench location, after quenching, and a local redistribution of trapped flux with increasing RF field.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB036
About •	Received ※ 15 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 05 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB057	Implementation of the Test Bench for the PIP-II LB650 Cryomodules at CEA	cryomodule, cavity, SRF, operation	243
	H. Jenhani, N. Bazin, Q. Bertrand, P. Brédy, L. Maurice, O. Piquet, P. Sahuquet, C. Simon CEA-IRFU, Gif-sur-Yvette, France
	The Proton Improvement Plan II (PIP-II) at Fermilab is the first U.S. accelerator project that will have significant contributions from international partners. As a part of the French In-Kind Contributions to this project, CEA will provide ten 650 MHz low-beta cryomodules (LB650) equipped with LASA-INFN (Italy) and VECC-DAE (India) cavities and Fermilab power couplers and RF tuning systems. CEA is accordingly in charge of the design, manufacturing, assembly and testing of these cryomodules. This paper presents the future implementation of the test stand dedicated to the cryogenic and RF power testing of the LB650 cryomodules. The choice of the equipment and the current status will be detailed, as well.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB057
About •	Received ※ 19 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 05 July 2023
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MOPMB065	Design Status of BCC Cryomodule for LCLS-II HE	cryomodule, cavity, simulation, solenoid	263
	C.S. Narug, T.T. Arkan, S. Cheban, M. Chen, B.D. Hartsell, J.A. Kaluzny, V.S. Kashikhin, Y.M. Orlov 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. A Buncher or Capture Cavity (BCC) Cryomodule is currently in development at Fermilab for use in a second injector for LCLS-II-HE. The BCC Cryomodule is designed to contain one 1.3 GHz cavity and one solenoid magnet as part of a 100MeV low emittance injector. The design considerations for the Cryomodule are similar to the LCLS-II cryomodule with additional requirements to account for additional vacuum loading at the end of this vessel due to the termination of the insulating vacuum. To accomplish this design, the cryomodule is being developed using the experience gained during the development of the LCLS-II cryomodule. The design, analysis, and status of the Cryomodule will be discussed.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB065
About •	Received ※ 18 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 13 July 2023
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TUPTB033	On the Way to a 10 MeV, Conduction-Cooled, Compact SRF Accelerator	cavity, SRF, electron, simulation	471
	H. Vennekate, G. Cheng, G. Ciovati, J. Guo, K.A. Harding, J. Henry, U. Pudasaini, R.A. Rimmer JLab, Newport News, VA, USA A. Castilla JLAB, Newport News, USA F.E. Hannon Phase Space Tech, Bjärred, Sweden D.A. Packard GA, San Diego, California, USA J. Rathke TechSource, Los Alamos, New Mexico, USA T. Schultheiss TJS Technologies, Commack, New York, USA
	Funding: The presentation has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. After the success of designing a compact 1 MeV, 1 MW accelerator based on conduction-cooled SRF, Jefferson Lab is now pursuing a concept to provide a tenfold increase of the beam energy. The higher energy significantly extends the range of applications for environmental remediation and industry in general. The obvious challenge for SRF is to move from a single-cell to a multicell cavity while maintaining high efficiency and the ability to operate the machine without a complex cryogenic plant. The contribution presents the latest results of this design study with respect to its centerpiece, a Nb₃Sn coated 915 MHz five-cell cavity and its corresponding RF components, i.e. FPC and HOM absorber, as well as the conduction-cooling concept based on commercially available cryocoolers.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB033
About •	Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 18 July 2023
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TUPTB043	Development of 3-Cell Traveling Wave SRF Cavity	cavity, resonance, SRF, GUI	517
	F. Furuta, T.N. Khabiboulline, K.E. McGee, V.P. Yakovlev Fermilab, Batavia, Illinois, USA P.V. Avrakhov, R.A. Kostin Euclid TechLabs, Solon, Ohio, 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 Traveling wave SRF cavity is a new technology and requires a multi-stage process for development. Concep-tual designs have been proposed to adopt TW resonance in an SRF cavity The early stages of developments have been funded by several SBIR grants to Euclid Techlabs which were completed in collaboration with Fermilab. A 3-cell proof-of-principle TW cavity was fabricated as part of that and demonstrated the TW resonance excita-tion at room temperature. A TW resonance control tuner for the 3-cell was also fabricated and the preliminary tests were performed. Now, the 3-cell cavity is being processed and prepared for the first cryogenic testing.
	Poster TUPTB043 [1.743 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB043
About •	Received ※ 17 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 02 July 2023
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WEIXA02	Results of the R&D RF Testing Campaign of 1.3 GHz Nb/Cu Cavities	cavity, SRF, niobium, operation	621
	L. Vega Cid, S. Atieh, G. Bellini, A. Bianchi, L.M.A. Ferreira, C. Pereira Carlos, G.J. Rosaz, W. Venturini Delsolaro CERN, Meyrin, Switzerland S.B. Leith European Organization for Nuclear Research (CERN), Geneva, Switzerland
	In the context of the R&D program on Nb/Cu carried out at CERN, a total of 25 tests have been performed since 2021. This talk will present these results. Three different manufacturing techniques have been used to produce the copper substrates, in order to investigate which is the most suitable in terms of quality and economy of scale. On one hand, the focus has been on optimizing the surface resistance at 4.2K, as this will be the operating temperature of FCC. The results at this temperature are encouraging, showing repeatable and optimized RF performance. On the other hand, RF tests have been done at 1.85 K too aiming at deepening the knowledge of the mechanisms behind the Q slope. This is key to work on the mitigation of this phenomenon and ultimately to extend the application of this technology to high energy, high gradient accelerators. The influence of the thermal cycles has been thoroughly investigated. A systematic improvement has been observed of both the Q slope and the residual resistance with slow thermal cycles.
	Slides WEIXA02 [5.385 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEIXA02
About •	Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 02 July 2023
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WEPWB064	Performance Analysis from ESS Cryomodule Testing at CEA	cavity, cryomodule, controls, electron	727
	O. Piquet, C. Arcambal, Q. Bertrand, P. Bosland, E. Cenni, G. Devanz, T. Hamelin CEA-IRFU, Gif-sur-Yvette, France P. Sahuquet CEA-DRF-IRFU, France
	CEA Saclay is in charge of the production of 30 elliptical cavities cryomodule as part of the in Kind contribution to the ESS superconducting. The two medium and high beta prototypes and the three first of each type of the series cryomodules have been tested at CEA in slightly different conditions than at ESS (both in terms of cryogenic operation as well as RF conditions). The goal of these tests was to validate the assembly procedure before the delivery of the series to ESS where the final acceptance tests are performed. This paper summarizes the main results obtained during the tests at CEA with a particular attention to the field emission behaviour.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB064
About •	Received ※ 20 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 07 July 2023
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WEPWB073	Prototype HB650 Cryomodule Heat Loads Simulations	cryomodule, cavity, SRF, experiment	755
	G. Coladonato University of Illinois at Chicago, Chicago, USA D. Passarelli, V. Roger 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. During the design stages of the PIP-II cryomodules, many analytical calculations and FEA have been performed on simpler geometry in order to estimate the heat loads and also to optimize the design. To better analyze the cryomodule cold tests, simulations have been performed with MATLAB to determine the temperature of the main components during cool down and to determine the heat loads of the cryomodule. These simulations have been applied to the High Beta 650 MHz prototype cryomodule design and compared to the cold tests performed on it.
	Poster WEPWB073 [1.981 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB073
About •	Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 28 June 2023
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WEPWB082	Operational Experience with Turn-Key SRF Systems for Small Accelerators Like MESA	SRF, cryomodule, operation, cavity	768
	T. Stengler, K. Aulenbacher, F. Hug, P.S. Plattner KPH, Mainz, Germany
	Funding: The work is funded by the German Research Foundation (DFG) under the Cluster of Excellence "PRISMA+" EXC 2118/2019 and the Federal Ministry of Education and Research (BMBF) through project 05H21UMRB1 New SRF-based accelerator development at sites without long-term experience in SRF development is a major challenge. Especially in-house development of cryomodules is an almost impossible obstacle to overcome for small projects. To minimize such obstacles, turn-key SRF systems provided by industry can be of great importance. For the multiturn ERL MESA, which is currently under construction at Johannes Gutenberg-Universität Mainz, two turnkey cryomodules have been purchased from industry and successfully tested. The specifications of a design gradient of 12.5 MV/m in CW operation with an unloaded Q of 1.25*10¹⁰ at 1.8 K had to be met. Since the design of the modules had to be modified for high current CW operation, a close cooperation with the manufacturer was of great importance. By purchasing such a turn-key SRF system, the MESA project successfully established the SRF accelerator technology at the site within six years. This was achieved through close monitoring of the manufacturing process and close cooperation with the manufacturer. An overview of the experience with the successful technology transfer of a complete turn-key SRF system for small accelerators will be given.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB082
About •	Received ※ 25 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 03 August 2023
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WEPWB125	Thermodynamic Properties of Srf Niobium	cavity, SRF, niobium, radio-frequency	884
	P. Dhakal JLab, Newport News, Virginia, USA
	Funding: This is authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05- 06OR23177. Bulk and thin films of niobium are the materials of choice in fabricating superconducting radio frequency (SRF) cavities for modern particle accelerators and quantum computing applications. The thermodynamic properties of Nb are of particular interest in heat management in cryogenic environments. Here, we report the results of measurements of the thermodynamic properties of niobium used in the fabrication of superconducting radio frequency (SRF) cavities. The temperature and magnetic field dependence of thermal conductivity, Seebeck coefficient, and specific heat capacity was measured on bulk niobium samples.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB125
About •	Received ※ 11 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 04 July 2023
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Paper

Title

Other Keywords

Page

MOIAA03

Progresses in the ESS Superconducting Linac Installation

cryomodule, linac, MMI, operation

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)

MOPMB010

Analysis of Semiconductor Components as Temperature Sensors for Cryogenic Investigation of SRF Materials

cavity, controls, experiment, SRF

80

A. Cierpka, S. Keckert, J. Knobloch, F. Kramer, O. Kugeler
HZB, Berlin, Germany

Temperature mapping systems have been used for many years to detect local heating in an SRF cavity surface or materials sample. They require a large number of temperature sensors. Most often, low-cost Allen-Bradley resistors are used for this purpose. Since they have poor sensitivity and reproducibility above 4 K, sensor alternatives that combine the precision of Cernox sensors with the low-cost of Allen-Bradley resistors would be highly desirable. In this work various semiconductor components that exhibit a temperature dependent electrical response, such as diodes and LEDs were analyzed with respect to sensitivity, reproducibility and response speed in a temperature range between 6.5 K and 22 K. In this range, many diodes and LEDs were found to be more sensitive than Cernox sensors. However, in some components the response time was slow - possibly due to poor thermal contact.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB010

About •

Received ※ 08 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 17 July 2023

Cite •

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

MOPMB014

NbTi Thin Film SRF Cavities for Dark Matter Search

cavity, target, SRF, photon

96

G. Marconato
Università degli Studi di Padova, Padova, Italy
D. Alesini, A. D’Elia, D. Di Gioacchino, C. Gatti, C. Ligi, G. Maccarrone, A. Rettaroli, S. Tocci
LNF-INFN, Frascati, Italy
O. Azzolini, R. Caforio, E. Chyhyrynets, D. Fonnesu, D. Ford, V.A. Garcia, G. Keppel, C. Pira, A. Salmaso, F. Stivanello
INFN/LNL, Legnaro (PD), Italy
C. Braggio
Univ. degli Studi di Padova, Padova, Italy
D. D’Agostino, U. Gambardella
INFN-Salerno, Baronissi, Salerno, Italy
S. Posen
Fermilab, Batavia, Illinois, USA

Funding: Resources from U.S. DOE, Ofce of Science, NQISRC, SQMS contract No DE-AC02-07CH11359. Also from EU’s Horizon 2020 Research and Innovation programme, Grant Agreement No 101004730; INFN CSNV exp. SAMARA
The search for dark matter is now looking at ALPs (axion-like particles) as a very promising candidate to understand our universe. Within this framework, we explore the possibility to use NbTi thin film coatings on Cu resonating cavities to investigate the presence of axions in the range of 35-45 µeV mass by coupling the axion to a very strong magnetic field inside the cavity, causing its conversion to a photon which is subsequently detected. In this work the chemical treatments and DC magnetron sputtering details of the preparation of 9 GHz, 7 GHz, and 3.9 GHz resonant cavities and their quality factor measurements at different applied magnetic fields are presented.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB014

About •

Received ※ 18 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 26 July 2023

Cite •

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

MOPMB017

Development of a Thermal Conductance Instrument for Niobium at Cryogenic Temperatures

cavity, niobium, ECR, operation

109

C. Saribal, C. Martens
University of Hamburg, Hamburg, Germany
W. Hillert, M. Wenskat
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

Funding: University of Hamburg
Particle accelerators form an important tool in a variety of research fields. In an effort to reduce operation costs while maintaining high energies, their accelerating structures are steadily improved towards higher accelerating fields and lower RF losses. Stable operation of such a cavity generally requires Joule-heating, generated in its walls, to be conducted to an outer helium bath. Therefore, it is of interest to experimentally evaluate how present and future cavity treatments affect thermal characteristics. We present an instrument for measuring the thermal performance of SRF cavity materials at cryogenic temperatures. Pairs of niobium disks are placed inside of a liquid helium bath and a temperature gradient is generated across them to obtain total thermal resistance for temperatures below 2 Kelvin. To get an idea of the instruments sensitivity and how standard cavity treatments influence thermal resistance, samples are tested post fabrication, polishing and 800 °C baking. The first tests show the commissioning of our newly set up system and if it is feasible to observe relevant changes and evaluate new and promising cavity treatments such as SIS structures.

Poster MOPMB017 [3.217 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB017

About •

Received ※ 17 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 01 July 2023

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

MOPMB036

Magnetic Field Mapping of a Large-Grain 1.3 GHz Single-Cell Cavity

cavity, radio-frequency, niobium, SRF

172

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

Funding: This work was supported by the National Science Foundation under Grant No. PHY 100614-010. G.C. is supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A new magnetic field mapping system for 1.3 GHz single-cell cavities was developed in order to reveal the impact of ambient magnetic field and temperature gradients during cool-down on the flux trapping phenomenon. Measurements were done at 2 K for different cool-down conditions of a large-grain cavity before and after 120 °C bake. The fraction of applied magnetic field trapped in the cavity walls was ~ 50% after slow cool-down and ~20% after fast cool-down. The results showed a weak correlation between between trapped flux locations and hot-spots causing the high-field Q-slope. The results also showed an increase of the trapped flux at the quench location, after quenching, and a local redistribution of trapped flux with increasing RF field.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB036

About •

Received ※ 15 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 05 July 2023

Cite •

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

MOPMB057

Implementation of the Test Bench for the PIP-II LB650 Cryomodules at CEA

cryomodule, cavity, SRF, operation

243

H. Jenhani, N. Bazin, Q. Bertrand, P. Brédy, L. Maurice, O. Piquet, P. Sahuquet, C. Simon
CEA-IRFU, Gif-sur-Yvette, France

The Proton Improvement Plan II (PIP-II) at Fermilab is the first U.S. accelerator project that will have significant contributions from international partners. As a part of the French In-Kind Contributions to this project, CEA will provide ten 650 MHz low-beta cryomodules (LB650) equipped with LASA-INFN (Italy) and VECC-DAE (India) cavities and Fermilab power couplers and RF tuning systems. CEA is accordingly in charge of the design, manufacturing, assembly and testing of these cryomodules. This paper presents the future implementation of the test stand dedicated to the cryogenic and RF power testing of the LB650 cryomodules. The choice of the equipment and the current status will be detailed, as well.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB057

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Received ※ 19 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 05 July 2023

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MOPMB065

Design Status of BCC Cryomodule for LCLS-II HE

cryomodule, cavity, simulation, solenoid

263

C.S. Narug, T.T. Arkan, S. Cheban, M. Chen, B.D. Hartsell, J.A. Kaluzny, V.S. Kashikhin, Y.M. Orlov
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.
A Buncher or Capture Cavity (BCC) Cryomodule is currently in development at Fermilab for use in a second injector for LCLS-II-HE. The BCC Cryomodule is designed to contain one 1.3 GHz cavity and one solenoid magnet as part of a 100MeV low emittance injector. The design considerations for the Cryomodule are similar to the LCLS-II cryomodule with additional requirements to account for additional vacuum loading at the end of this vessel due to the termination of the insulating vacuum. To accomplish this design, the cryomodule is being developed using the experience gained during the development of the LCLS-II cryomodule. The design, analysis, and status of the Cryomodule will be discussed.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB065

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Received ※ 18 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 13 July 2023

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TUPTB033

On the Way to a 10 MeV, Conduction-Cooled, Compact SRF Accelerator

cavity, SRF, electron, simulation

471

H. Vennekate, G. Cheng, G. Ciovati, J. Guo, K.A. Harding, J. Henry, U. Pudasaini, R.A. Rimmer
JLab, Newport News, VA, USA
A. Castilla
JLAB, Newport News, USA
F.E. Hannon
Phase Space Tech, Bjärred, Sweden
D.A. Packard
GA, San Diego, California, USA
J. Rathke
TechSource, Los Alamos, New Mexico, USA
T. Schultheiss
TJS Technologies, Commack, New York, USA

Funding: The presentation has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
After the success of designing a compact 1 MeV, 1 MW accelerator based on conduction-cooled SRF, Jefferson Lab is now pursuing a concept to provide a tenfold increase of the beam energy. The higher energy significantly extends the range of applications for environmental remediation and industry in general. The obvious challenge for SRF is to move from a single-cell to a multicell cavity while maintaining high efficiency and the ability to operate the machine without a complex cryogenic plant. The contribution presents the latest results of this design study with respect to its centerpiece, a Nb₃Sn coated 915 MHz five-cell cavity and its corresponding RF components, i.e. FPC and HOM absorber, as well as the conduction-cooling concept based on commercially available cryocoolers.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB033

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Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 18 July 2023

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TUPTB043

Development of 3-Cell Traveling Wave SRF Cavity

cavity, resonance, SRF, GUI

517

F. Furuta, T.N. Khabiboulline, K.E. McGee, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA
P.V. Avrakhov, R.A. Kostin
Euclid TechLabs, Solon, Ohio, 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
Traveling wave SRF cavity is a new technology and requires a multi-stage process for development. Concep-tual designs have been proposed to adopt TW resonance in an SRF cavity The early stages of developments have been funded by several SBIR grants to Euclid Techlabs which were completed in collaboration with Fermilab. A 3-cell proof-of-principle TW cavity was fabricated as part of that and demonstrated the TW resonance excita-tion at room temperature. A TW resonance control tuner for the 3-cell was also fabricated and the preliminary tests were performed. Now, the 3-cell cavity is being processed and prepared for the first cryogenic testing.

Poster TUPTB043 [1.743 MB]

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reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB043

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Received ※ 17 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 02 July 2023

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WEIXA02

Results of the R&D RF Testing Campaign of 1.3 GHz Nb/Cu Cavities

cavity, SRF, niobium, operation

621

L. Vega Cid, S. Atieh, G. Bellini, A. Bianchi, L.M.A. Ferreira, C. Pereira Carlos, G.J. Rosaz, W. Venturini Delsolaro
CERN, Meyrin, Switzerland
S.B. Leith
European Organization for Nuclear Research (CERN), Geneva, Switzerland

In the context of the R&D program on Nb/Cu carried out at CERN, a total of 25 tests have been performed since 2021. This talk will present these results. Three different manufacturing techniques have been used to produce the copper substrates, in order to investigate which is the most suitable in terms of quality and economy of scale. On one hand, the focus has been on optimizing the surface resistance at 4.2K, as this will be the operating temperature of FCC. The results at this temperature are encouraging, showing repeatable and optimized RF performance. On the other hand, RF tests have been done at 1.85 K too aiming at deepening the knowledge of the mechanisms behind the Q slope. This is key to work on the mitigation of this phenomenon and ultimately to extend the application of this technology to high energy, high gradient accelerators. The influence of the thermal cycles has been thoroughly investigated. A systematic improvement has been observed of both the Q slope and the residual resistance with slow thermal cycles.

Slides WEIXA02 [5.385 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEIXA02

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Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 02 July 2023

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WEPWB064

Performance Analysis from ESS Cryomodule Testing at CEA

cavity, cryomodule, controls, electron

727

O. Piquet, C. Arcambal, Q. Bertrand, P. Bosland, E. Cenni, G. Devanz, T. Hamelin
CEA-IRFU, Gif-sur-Yvette, France
P. Sahuquet
CEA-DRF-IRFU, France

CEA Saclay is in charge of the production of 30 elliptical cavities cryomodule as part of the in Kind contribution to the ESS superconducting. The two medium and high beta prototypes and the three first of each type of the series cryomodules have been tested at CEA in slightly different conditions than at ESS (both in terms of cryogenic operation as well as RF conditions). The goal of these tests was to validate the assembly procedure before the delivery of the series to ESS where the final acceptance tests are performed. This paper summarizes the main results obtained during the tests at CEA with a particular attention to the field emission behaviour.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB064

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Received ※ 20 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 07 July 2023

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WEPWB073

Prototype HB650 Cryomodule Heat Loads Simulations

cryomodule, cavity, SRF, experiment

755

G. Coladonato
University of Illinois at Chicago, Chicago, USA
D. Passarelli, V. Roger
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.
During the design stages of the PIP-II cryomodules, many analytical calculations and FEA have been performed on simpler geometry in order to estimate the heat loads and also to optimize the design. To better analyze the cryomodule cold tests, simulations have been performed with MATLAB to determine the temperature of the main components during cool down and to determine the heat loads of the cryomodule. These simulations have been applied to the High Beta 650 MHz prototype cryomodule design and compared to the cold tests performed on it.

Poster WEPWB073 [1.981 MB]

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reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB073

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Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 28 June 2023

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WEPWB082

Operational Experience with Turn-Key SRF Systems for Small Accelerators Like MESA

SRF, cryomodule, operation, cavity

768

T. Stengler, K. Aulenbacher, F. Hug, P.S. Plattner
KPH, Mainz, Germany

Funding: The work is funded by the German Research Foundation (DFG) under the Cluster of Excellence "PRISMA+" EXC 2118/2019 and the Federal Ministry of Education and Research (BMBF) through project 05H21UMRB1
New SRF-based accelerator development at sites without long-term experience in SRF development is a major challenge. Especially in-house development of cryomodules is an almost impossible obstacle to overcome for small projects. To minimize such obstacles, turn-key SRF systems provided by industry can be of great importance. For the multiturn ERL MESA, which is currently under construction at Johannes Gutenberg-Universität Mainz, two turnkey cryomodules have been purchased from industry and successfully tested. The specifications of a design gradient of 12.5 MV/m in CW operation with an unloaded Q of 1.25*10¹⁰ at 1.8 K had to be met. Since the design of the modules had to be modified for high current CW operation, a close cooperation with the manufacturer was of great importance. By purchasing such a turn-key SRF system, the MESA project successfully established the SRF accelerator technology at the site within six years. This was achieved through close monitoring of the manufacturing process and close cooperation with the manufacturer. An overview of the experience with the successful technology transfer of a complete turn-key SRF system for small accelerators will be given.

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reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB082

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Received ※ 25 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 03 August 2023

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WEPWB125

Thermodynamic Properties of Srf Niobium

cavity, SRF, niobium, radio-frequency

884

P. Dhakal
JLab, Newport News, Virginia, USA

Funding: This is authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05- 06OR23177.
Bulk and thin films of niobium are the materials of choice in fabricating superconducting radio frequency (SRF) cavities for modern particle accelerators and quantum computing applications. The thermodynamic properties of Nb are of particular interest in heat management in cryogenic environments. Here, we report the results of measurements of the thermodynamic properties of niobium used in the fabrication of superconducting radio frequency (SRF) cavities. The temperature and magnetic field dependence of thermal conductivity, Seebeck coefficient, and specific heat capacity was measured on bulk niobium samples.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB125

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Received ※ 11 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 04 July 2023

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