LINAC2022 - List of Keywords (cryogenics)

Paper	Title	Other Keywords	Page
MOPOGE19	Preliminary Study on the Cryogenic Control System Within RF Superconductive Linac Projects	controls, PLC, cryomodule, linac	197
	H. Sibileau, M.L. Beniken ACS, Orsay, France T. Junquera Accelerators and Cryogenic Systems, Orsay, France D. Masson ISII-TECH, Saint-Etienne-du-Rouvray, France
	Several RF Superconductive LINAC projects are underway in different laboratories around the world, with various objectives such as research in physics, irradiation tests, production of radioisotopes for medical purposes. Superconducting operation of the accelerating cavities requires them to be maintained at cryogenic temperatures (2K - 4K) by the use of cryogenic fluids. This requires a complete cryogenic control system, including sensors, actuators, local controllers and PLCs. We describe the process by which the preliminary design of the cryogenic control system for the accelerator’s cryomodules and valve boxes may be built. It starts with the functional and performance requirements of the system, followed by the definition of use cases and the study of the necessary cryogenic instrumentation. This leads to a preliminary design of the architecture of the cryogenic control system using Siemens hardware, as well as cryogenic sequences describing standard phases of operation of the LINAC. We also discuss how to take advantage of the modularity of cryomodules for control system implementation and some recent developments in PLC simulation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE19
About •	Received ※ 24 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 11 September 2022 — Issue date ※ 16 October 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOJO15	Commissioning of UKRI-STFC SRF Vertical Test and HPR Reprocessing Facility	cavity, SRF, MMI, vacuum	380
	M.D. Pendleton, A.E.T. Akintola, R.K. Buckley, G. Collier, K.D. Dumbell, M.J. Ellis, S. Hitchen, P.C. Hornickel, G. Hughes, C.R. Jenkins, A.J. May, P.A. McIntosh, K.J. Middleman, A.J. Moss, S.M. Pattalwar, J.O.W. Poynton, P.A. Smith, A.E. Wheelhouse, S. Wilde STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom G. Jones, M. Lowe, D.A. Mason, G. Miller, C. Mills, J. Mutch, A. Oates, J.T.G. Wilson STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	Mark Pendleton, et al. The UK’s first and only vertical test facility and associated cleanroom reprocessing suite has been developed, commissioned, and entered steady-state operations at the UKRI-STFC Daresbury Laboratory. The facility is capable of 2 K testing of 3 jacketed SRF cavities in a horizontal configuration per 2-week test cycle. We report on the associated cryogenic, RF, UHV, mechanical, cleanroom, and HPR infrastructure. SRF cavity workflows have been developed to meet the requirements of the ESS high beta cavity project within a newly developed quality management system, SuraBee, in accordance with ISO9001. To support standardisation of measurements across the collaboration, reference cavities have been measured for cross-reference between CEA, DESY, and UKRI-STFC. We further report on commissioning objectives, observations, and continuous improvement activities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO15
About •	Received ※ 24 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 05 September 2022 — Issue date ※ 08 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOGE02	Three Years of Operation of the SPIRAL2 LINAC: Cryogenics and Superconducting RF Feedback	cavity, cryomodule, operation, linac	479
	P.-E. Bernaudin, M. Aburas, M. Di Giacomo, A. Ghribi, P. Robillard, L. Valentin GANIL, Caen, France
	The superconducting LINAC of SPIRAL2 at the GANIL facility is in operation since October 2019. Its 26 super-conducting quarter wave resonating cavities (88 MHz) are operated at a nominal gradient of 6.5 MV/m, but most of the cavities can be operated up to 8 MV/m. They are integrated into 19 cryomodules and cooled down at 4 K by a dedicated refrigeration cryogenic system. In this paper, we will present a feedback after five years of operation of the cryogenic system, focusing on the main problems that have been faced, and on the diverse evolutions performed in order to improve the cryogenic system and to increase its reliability. We will also provide a feedback of the superconducting cavities performances status after three years of operation
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE02
About •	Received ※ 27 July 2022 — Revised ※ 22 August 2022 — Accepted ※ 26 August 2022 — Issue date ※ 15 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOGE03	Advanced Cryogenic Process Control and Monitoring for the SPIRAL2 Superconducting LINAC	cavity, controls, linac, cryomodule	483
	A. Ghribi, M. Aburas, P.-E. Bernaudin, M. Di Giacomo, A.H. Trudel, Q. Tura GANIL, Caen, France P. Bonnay, F. Bonne CEA/INAC, Grenoble Cedex 9, France F. Millet CEA, Grenoble, France
	SPIRAL2 is a superconducting accelerator for protons, deuterons and heavy ions delivering a maximum beam power of 200 kW at 40 MeV (for deuteron beams). 26 superconducting quarter wave cavities are operated at 4.4 K, plunged in a liquid helium bath with a drastic phase separator pressure control. Previous years have seen the development of advanced process control for cryogenics allowing to cope with high heat load dynamics thanks to an automatic heat dissipation compensation and a model based control. The latter is based on models, using the Simcryogenics library, optimized and linearised in the Programmable Logic Controllers. The SPIRAL2 operation has demonstrated that such control allows to keep the specified conditions for RF and beam operation even at levels of heat load dissipation approaching the physical limits of the cryogenic system. These developments allowed to synthesise a virtual observer of the dynamic heat load dissipated by the cavities. The present paper summarises the development of such observer based on the physical thermodynamic model and on machine learning techniques.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE03
About •	Received ※ 24 August 2022 — Revised ※ 02 September 2022 — Accepted ※ 04 September 2022 — Issue date ※ 09 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOGE04	An Approach for Component-Level Analysis of Cryogenic Process in Superconducting LINAC Cryomodules	cryomodule, cavity, linac, multipactoring	487
	C. Lhomme IJCLab, ORSAY, France D. Berkowitz Zamora, M.D. Grosso Xavier SCK•CEN, Mol, Belgium F. Chatelet, P. Duthil, H. Saugnac Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France F. Dieudegard, C. Lhomme ACS, Orsay, France T. Junquera Accelerators and Cryogenic Systems, Orsay, France
	Powerful superconducting linear accelerators feature accelerating sections consisting in a series of cryomod-ules (CM), each hosting superconducting radiofrequency (SRF) cavities cooled by a cryogenic process. Despite the extensive instrumentation used for the tests and valida-tion of the prototype cryomodules, it is usually very complex to link the measured global thermodynamic efficiency to the individual component performance. Previous works showed methods for assessing the global efficiency and even for allocating performances to sets of components, but few went down to a component level. For that purpose, we developed a set of techniques based on customized instrumentation, on dedicated test proto-cols, and on model-based analysis tools. In practice, we exposed the components to various operating conditions and we compared the measured data to the results from a detailed dynamic component model at the same condi-tions. This method was applied to the cryogenic debug-ging phase of the tests of the MINERVA prototype cry-omodule, which, despite the liquid helium shortage, led to an extensively detailed characterisation, for its valida-tion towards the serial construction.
	Poster TUPOGE04 [1.234 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE04
About •	Received ※ 20 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOGE09	Steady-State Cryogenic Operations for the UKRI-STFC Daresbury SRF Vertical Test Facility	cavity, operation, MMI, SRF	501
	A.J. May, A.E.T. Akintola, R.K. Buckley, G. Collier, K.D. Dumbell, S. Hitchen, P.C. Hornickel, G. Hughes, C.R. Jenkins, S.M. Pattalwar, M.D. Pendleton, P.A. Smith STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	A novel vertical test facility has been developed, commissioned, and entered steady-state operations at the UKRI-STFC Daresbury Laboratory. The cryostat is designed to test 3 jacketed superconducting RF cavities in a horizontal configuration in a single cool-down run at 2 K. The cavities are cooled with superfluid helium filled into their individual helium jackets. This reduces the liquid helium consumption by more than 70% in comparison with the conventional facilities operational elsewhere. The facility is currently undertaking a 2-year program to qualify 84 high-beta SRF cavities for the ESS (European Spallation Source) as part of the UK’s in-kind contribution. This paper reports on the steady-state operations, along with a detailed discussion of the cryogenic performance of the facility, including that of the cryoplant.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE09
About •	Received ※ 13 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 04 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOGE10	A Final Acceptance Test Kit for Superconducting RF Cryomodules	cryomodule, cavity, vacuum, SRF	504
	A.J. May, A.E.T. Akintola, S.M. Pattalwar, A. White STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	UKRI-STFC Daresbury Laboratory is currently undertaking several projects involving assembly of superconducting RF cryomodules, including HL-LHC crab cavities and PIP-II HB650 cavities. As part of the final acceptance tests before shipping of the modules, extensive leak testing, pressure testing, and thermal cycling with gaseous and liquid must be performed. A Final Acceptance Test kit (FAT-kit) has been developed to support these tests. The FAT-kit, designed as a single portable unit, sits as an interface module between the cryomodule under test and the required utilities (liquid cryogen supply and return, gaseous cryogen supply and return, warm gas supply and return, vacuum pumps, leak detectors, etc.). The kit features a valve manifold to make or break connections to, from, and between circuits in the cryomodule, safety groupings to provide protection for the circuits as required, and various instrumentation. We report here on the design and commissioning of the kit.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE10
About •	Received ※ 23 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 15 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOGE18	Operations of Copper Cavities at Cryogenic Temperatures	cavity, vacuum, coupling, experiment	533
	H. Wang, U. Ratzinger, M. Schuett IAP, Frankfurt am Main, Germany
	This work is focused on the anomalous skin effect in copper and how it affects the efficiency of copper-cavities in the temperature range 40-50 K. The quality factor Q of three coaxial cavities was measured over the temperature range from 10 K to room temperature in the experiment. The three coaxial cavities have the same structure, but different lengths, which correspond to resonant frequencies: around 100 MHz, 220 MHz and 340 MHz. Furthermore, the effects of copper-plating and additional baking in the vacuum oven on the quality factor Q are studied in the experiment. The motivation is to check the feasibility of an efficient, pulsed, ion linac, operated at cryogenic temperatures.
	Slides TUPOGE18 [1.115 MB]
	Poster TUPOGE18 [1.518 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE18
About •	Received ※ 22 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 03 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOGE09	Split Thin Film SRF 6 GHz Cavities	cavity, niobium, SRF, ISOL	814
	B.S. Sian, G. Burt, D.J. Seal Lancaster University, Lancaster, United Kingdom G. Burt, O.B. Malyshev, D.J. Seal, R. Valizadeh Cockcroft Institute, Warrington, Cheshire, United Kingdom O.B. Malyshev, R. Valizadeh STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom H.S. Marks Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
	Many current accelerators use cavities that are manufactured as two half cells that are electron beam welded together, the weld is across the peak surface current of the cavity. This weld can lead to large increases in surface resistance and limit the performance of thin film coated cavities. Many problems with the coating process for thin film Superconducting Radio Frequency (SRF) cavities are also due to this weld. Thin film SRF cavities can perform as well as bulk niobium cavities if the cavity is manufactured seamlessly, without any weld, as they have a more uniform surface, however, they are much more difficult and expensive to manufacture. A cavity with a split longitudinally, parallel to the direction of the electric field, would not need to be welded. These seamless cavities are easier to manufacture and coat. This opens the possibilities to coat with new materials and multilayer coatings. These cavities may allow SRF cavities to operate at significantly better parameters (higher quality factor and maximum accelerating field) than current state of the art cavities. This work discusses development and testing of longitudinally split seamless cavities at Daresbury Laboratory.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE09
About •	Received ※ 25 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 12 September 2022 — Issue date ※ 15 October 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOGE15	Measuring the Seebeck Coefficient at Cryogenic Temperatures for LCLS-II-HE Project	niobium, experiment, SRF, cryomodule	825
	L. Shpani, M. Ge, A.T. Holic, M. Liepe, J. Sears, N.M. Verboncoeur Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work is supported by the DOE LCLS-II HE Project. The Seebeck effect plays a crucial role during the cooldown procedure in SRF based accelerators, like LCLS-II at SLAC. The temperature-dependent Seebeck coefficient quantitatively measures the strength of electric potential induced by thermal gradients in metals. This effect is present in cryomodules and drives thermoelectric currents generating magnetic fields. These fields can get trapped in cavities and cause additional dissipation in RF fields. We have therefore designed and commissioned an experimental setup that does continuous measurements of the Seebeck coefficient for cryogenic temperatures ranging from 200K down to below 10K. We present results of the measurements of this coefficient for materials commonly used in cryomodules, such as niobium, titanium, niobium-titanium, silicon bronze, and stainless steel.
	Poster THPOGE15 [0.959 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE15
About •	Received ※ 27 August 2022 — Revised ※ 04 September 2022 — Accepted ※ 26 September 2022 — Issue date ※ 29 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOPOGE19

Preliminary Study on the Cryogenic Control System Within RF Superconductive Linac Projects

controls, PLC, cryomodule, linac

197

H. Sibileau, M.L. Beniken
ACS, Orsay, France
T. Junquera
Accelerators and Cryogenic Systems, Orsay, France
D. Masson
ISII-TECH, Saint-Etienne-du-Rouvray, France

Several RF Superconductive LINAC projects are underway in different laboratories around the world, with various objectives such as research in physics, irradiation tests, production of radioisotopes for medical purposes. Superconducting operation of the accelerating cavities requires them to be maintained at cryogenic temperatures (2K - 4K) by the use of cryogenic fluids. This requires a complete cryogenic control system, including sensors, actuators, local controllers and PLCs. We describe the process by which the preliminary design of the cryogenic control system for the accelerator’s cryomodules and valve boxes may be built. It starts with the functional and performance requirements of the system, followed by the definition of use cases and the study of the necessary cryogenic instrumentation. This leads to a preliminary design of the architecture of the cryogenic control system using Siemens hardware, as well as cryogenic sequences describing standard phases of operation of the LINAC. We also discuss how to take advantage of the modularity of cryomodules for control system implementation and some recent developments in PLC simulation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE19

About •

Received ※ 24 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 11 September 2022 — Issue date ※ 16 October 2022

Cite •

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

TUPOJO15

Commissioning of UKRI-STFC SRF Vertical Test and HPR Reprocessing Facility

cavity, SRF, MMI, vacuum

380

M.D. Pendleton, A.E.T. Akintola, R.K. Buckley, G. Collier, K.D. Dumbell, M.J. Ellis, S. Hitchen, P.C. Hornickel, G. Hughes, C.R. Jenkins, A.J. May, P.A. McIntosh, K.J. Middleman, A.J. Moss, S.M. Pattalwar, J.O.W. Poynton, P.A. Smith, A.E. Wheelhouse, S. Wilde
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
G. Jones, M. Lowe, D.A. Mason, G. Miller, C. Mills, J. Mutch, A. Oates, J.T.G. Wilson
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

Mark Pendleton, et al. The UK’s first and only vertical test facility and associated cleanroom reprocessing suite has been developed, commissioned, and entered steady-state operations at the UKRI-STFC Daresbury Laboratory. The facility is capable of 2 K testing of 3 jacketed SRF cavities in a horizontal configuration per 2-week test cycle. We report on the associated cryogenic, RF, UHV, mechanical, cleanroom, and HPR infrastructure. SRF cavity workflows have been developed to meet the requirements of the ESS high beta cavity project within a newly developed quality management system, SuraBee, in accordance with ISO9001. To support standardisation of measurements across the collaboration, reference cavities have been measured for cross-reference between CEA, DESY, and UKRI-STFC. We further report on commissioning objectives, observations, and continuous improvement activities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO15

About •

Received ※ 24 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 05 September 2022 — Issue date ※ 08 September 2022

Cite •

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

TUPOGE02

Three Years of Operation of the SPIRAL2 LINAC: Cryogenics and Superconducting RF Feedback

cavity, cryomodule, operation, linac

479

P.-E. Bernaudin, M. Aburas, M. Di Giacomo, A. Ghribi, P. Robillard, L. Valentin
GANIL, Caen, France

The superconducting LINAC of SPIRAL2 at the GANIL facility is in operation since October 2019. Its 26 super-conducting quarter wave resonating cavities (88 MHz) are operated at a nominal gradient of 6.5 MV/m, but most of the cavities can be operated up to 8 MV/m. They are integrated into 19 cryomodules and cooled down at 4 K by a dedicated refrigeration cryogenic system. In this paper, we will present a feedback after five years of operation of the cryogenic system, focusing on the main problems that have been faced, and on the diverse evolutions performed in order to improve the cryogenic system and to increase its reliability. We will also provide a feedback of the superconducting cavities performances status after three years of operation

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE02

About •

Received ※ 27 July 2022 — Revised ※ 22 August 2022 — Accepted ※ 26 August 2022 — Issue date ※ 15 September 2022

Cite •

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

TUPOGE03

Advanced Cryogenic Process Control and Monitoring for the SPIRAL2 Superconducting LINAC

cavity, controls, linac, cryomodule

483

A. Ghribi, M. Aburas, P.-E. Bernaudin, M. Di Giacomo, A.H. Trudel, Q. Tura
GANIL, Caen, France
P. Bonnay, F. Bonne
CEA/INAC, Grenoble Cedex 9, France
F. Millet
CEA, Grenoble, France

SPIRAL2 is a superconducting accelerator for protons, deuterons and heavy ions delivering a maximum beam power of 200 kW at 40 MeV (for deuteron beams). 26 superconducting quarter wave cavities are operated at 4.4 K, plunged in a liquid helium bath with a drastic phase separator pressure control. Previous years have seen the development of advanced process control for cryogenics allowing to cope with high heat load dynamics thanks to an automatic heat dissipation compensation and a model based control. The latter is based on models, using the Simcryogenics library, optimized and linearised in the Programmable Logic Controllers. The SPIRAL2 operation has demonstrated that such control allows to keep the specified conditions for RF and beam operation even at levels of heat load dissipation approaching the physical limits of the cryogenic system. These developments allowed to synthesise a virtual observer of the dynamic heat load dissipated by the cavities. The present paper summarises the development of such observer based on the physical thermodynamic model and on machine learning techniques.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE03

About •

Received ※ 24 August 2022 — Revised ※ 02 September 2022 — Accepted ※ 04 September 2022 — Issue date ※ 09 September 2022

Cite •

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

TUPOGE04

An Approach for Component-Level Analysis of Cryogenic Process in Superconducting LINAC Cryomodules

cryomodule, cavity, linac, multipactoring

487

C. Lhomme
IJCLab, ORSAY, France
D. Berkowitz Zamora, M.D. Grosso Xavier
SCK•CEN, Mol, Belgium
F. Chatelet, P. Duthil, H. Saugnac
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
F. Dieudegard, C. Lhomme
ACS, Orsay, France
T. Junquera
Accelerators and Cryogenic Systems, Orsay, France

Powerful superconducting linear accelerators feature accelerating sections consisting in a series of cryomod-ules (CM), each hosting superconducting radiofrequency (SRF) cavities cooled by a cryogenic process. Despite the extensive instrumentation used for the tests and valida-tion of the prototype cryomodules, it is usually very complex to link the measured global thermodynamic efficiency to the individual component performance. Previous works showed methods for assessing the global efficiency and even for allocating performances to sets of components, but few went down to a component level. For that purpose, we developed a set of techniques based on customized instrumentation, on dedicated test proto-cols, and on model-based analysis tools. In practice, we exposed the components to various operating conditions and we compared the measured data to the results from a detailed dynamic component model at the same condi-tions. This method was applied to the cryogenic debug-ging phase of the tests of the MINERVA prototype cry-omodule, which, despite the liquid helium shortage, led to an extensively detailed characterisation, for its valida-tion towards the serial construction.

Poster TUPOGE04 [1.234 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE04

About •

Received ※ 20 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022

Cite •

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

TUPOGE09

Steady-State Cryogenic Operations for the UKRI-STFC Daresbury SRF Vertical Test Facility

cavity, operation, MMI, SRF

501

A.J. May, A.E.T. Akintola, R.K. Buckley, G. Collier, K.D. Dumbell, S. Hitchen, P.C. Hornickel, G. Hughes, C.R. Jenkins, S.M. Pattalwar, M.D. Pendleton, P.A. Smith
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

A novel vertical test facility has been developed, commissioned, and entered steady-state operations at the UKRI-STFC Daresbury Laboratory. The cryostat is designed to test 3 jacketed superconducting RF cavities in a horizontal configuration in a single cool-down run at 2 K. The cavities are cooled with superfluid helium filled into their individual helium jackets. This reduces the liquid helium consumption by more than 70% in comparison with the conventional facilities operational elsewhere. The facility is currently undertaking a 2-year program to qualify 84 high-beta SRF cavities for the ESS (European Spallation Source) as part of the UK’s in-kind contribution. This paper reports on the steady-state operations, along with a detailed discussion of the cryogenic performance of the facility, including that of the cryoplant.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE09

About •

Received ※ 13 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 04 September 2022

Cite •

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

TUPOGE10

A Final Acceptance Test Kit for Superconducting RF Cryomodules

cryomodule, cavity, vacuum, SRF

504

A.J. May, A.E.T. Akintola, S.M. Pattalwar, A. White
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

UKRI-STFC Daresbury Laboratory is currently undertaking several projects involving assembly of superconducting RF cryomodules, including HL-LHC crab cavities and PIP-II HB650 cavities. As part of the final acceptance tests before shipping of the modules, extensive leak testing, pressure testing, and thermal cycling with gaseous and liquid must be performed. A Final Acceptance Test kit (FAT-kit) has been developed to support these tests. The FAT-kit, designed as a single portable unit, sits as an interface module between the cryomodule under test and the required utilities (liquid cryogen supply and return, gaseous cryogen supply and return, warm gas supply and return, vacuum pumps, leak detectors, etc.). The kit features a valve manifold to make or break connections to, from, and between circuits in the cryomodule, safety groupings to provide protection for the circuits as required, and various instrumentation. We report here on the design and commissioning of the kit.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE10

About •

Received ※ 23 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 15 September 2022

Cite •

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

TUPOGE18

Operations of Copper Cavities at Cryogenic Temperatures

cavity, vacuum, coupling, experiment

533

H. Wang, U. Ratzinger, M. Schuett
IAP, Frankfurt am Main, Germany

This work is focused on the anomalous skin effect in copper and how it affects the efficiency of copper-cavities in the temperature range 40-50 K. The quality factor Q of three coaxial cavities was measured over the temperature range from 10 K to room temperature in the experiment. The three coaxial cavities have the same structure, but different lengths, which correspond to resonant frequencies: around 100 MHz, 220 MHz and 340 MHz. Furthermore, the effects of copper-plating and additional baking in the vacuum oven on the quality factor Q are studied in the experiment. The motivation is to check the feasibility of an efficient, pulsed, ion linac, operated at cryogenic temperatures.

Slides TUPOGE18 [1.115 MB]

Poster TUPOGE18 [1.518 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE18

About •

Received ※ 22 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 03 September 2022

Cite •

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

THPOGE09

Split Thin Film SRF 6 GHz Cavities

cavity, niobium, SRF, ISOL

814

B.S. Sian, G. Burt, D.J. Seal
Lancaster University, Lancaster, United Kingdom
G. Burt, O.B. Malyshev, D.J. Seal, R. Valizadeh
Cockcroft Institute, Warrington, Cheshire, United Kingdom
O.B. Malyshev, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
H.S. Marks
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

Many current accelerators use cavities that are manufactured as two half cells that are electron beam welded together, the weld is across the peak surface current of the cavity. This weld can lead to large increases in surface resistance and limit the performance of thin film coated cavities. Many problems with the coating process for thin film Superconducting Radio Frequency (SRF) cavities are also due to this weld. Thin film SRF cavities can perform as well as bulk niobium cavities if the cavity is manufactured seamlessly, without any weld, as they have a more uniform surface, however, they are much more difficult and expensive to manufacture. A cavity with a split longitudinally, parallel to the direction of the electric field, would not need to be welded. These seamless cavities are easier to manufacture and coat. This opens the possibilities to coat with new materials and multilayer coatings. These cavities may allow SRF cavities to operate at significantly better parameters (higher quality factor and maximum accelerating field) than current state of the art cavities. This work discusses development and testing of longitudinally split seamless cavities at Daresbury Laboratory.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE09

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Received ※ 25 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 12 September 2022 — Issue date ※ 15 October 2022

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THPOGE15

Measuring the Seebeck Coefficient at Cryogenic Temperatures for LCLS-II-HE Project

niobium, experiment, SRF, cryomodule

825

L. Shpani, M. Ge, A.T. Holic, M. Liepe, J. Sears, N.M. Verboncoeur
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work is supported by the DOE LCLS-II HE Project.
The Seebeck effect plays a crucial role during the cooldown procedure in SRF based accelerators, like LCLS-II at SLAC. The temperature-dependent Seebeck coefficient quantitatively measures the strength of electric potential induced by thermal gradients in metals. This effect is present in cryomodules and drives thermoelectric currents generating magnetic fields. These fields can get trapped in cavities and cause additional dissipation in RF fields. We have therefore designed and commissioned an experimental setup that does continuous measurements of the Seebeck coefficient for cryogenic temperatures ranging from 200K down to below 10K. We present results of the measurements of this coefficient for materials commonly used in cryomodules, such as niobium, titanium, niobium-titanium, silicon bronze, and stainless steel.

Poster THPOGE15 [0.959 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE15

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Received ※ 27 August 2022 — Revised ※ 04 September 2022 — Accepted ※ 26 September 2022 — Issue date ※ 29 September 2022

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