SRF2023 - List of Authors (Reschke, D.)

Paper	Title	Page
MOPMB021	Correlating Lambda Shift Measurements with RF Performance in Mid-T Heat Treated Cavities	124
SUSPB010	use link to see paper's listing under its alternate paper code
	R. Ghanbari, G.K. Deyu, W. Hillert, R. Monroy-Villa, M. Wenskat University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany C. Bate, D. Reschke, L. Steder, J.C. Wolff DESY, Hamburg, Germany
	Funding: This work was supported by the BMBF under the research grants 05K19GUB and 05H2021. Heat treatment procedures have been identified as cru-cial for the performance of niobium SRF cavities, which are the key technology of modern accelerators. The so called "mid-T heat treatments", invert the dependence of losses on the applied accelerating field (anti-Q slope) and significantly reduce the absolute value of losses. The mechanism behind these improvements is still under investigation, and further research is needed to fully understand the principle processes involved. Anomalies in the frequency shift near the transition temperature (Tc), known as "dip" can provide insight into fundamental material properties and allow us to study the relation-ship of frequency response with surface treatments. Therefore, we have measured the frequency versus temperature of multiple mid-T heat treated cavities with different recipes and studied the correlation of SRF properties with frequency shift features. The maximum quality factor correlates with two such shift features, namely the dip magnitude per temperature width and the total frequency shift.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB021
About •	Received ※ 20 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 15 August 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB022	Recent mid-T Single-Cell Treatments R&D at DESY	129
	C. Bate, D. Reschke, J. Schaffran, L. Steder, L. Trelle, H. Weise DESY, Hamburg, Germany
	The challenge of improving the performance of SRF cavities is being faced worldwide. One approach is to modify the superconducting surface properties through certain baking procedures. Recently a niobium retort furnace placed directly under an ISO4 clean room has been refurbished at DESY. Thanks to an inter-vacuum chamber and cryopumps, with high purity values in the mass spectrum it is working in the UHV range of 2·10^-8 mbar. The medium temperature (mid-T) heat treatments around 300°C are promising and successfully deliver reproducible very high Q₀ values of 2-5·10¹⁰ at medium field strengths of 16 MV/m. Since the first DESY and ZRI mid-T campaign yielded promising results, further results of 1.3 GHz single-cell cavities are presented here after several modified treatments of the mid-T recipe. In addition, samples were added to each treatment, the RRR value change was examined, and surface analyses were subsequently performed. The main focus of the sample study is the precise role of the changes in the concentration of impurities on the surface. In particular, the change in oxygen content due to diffusion processes is suspected to be the cause of enhancing the performance.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB022
About •	Received ※ 18 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 01 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB058	Summary of the Superconducting Rf Measurements in AMTF Hall at DESY	248
	M. Wiencek, K. Kasprzak, D. Kostin, D. Reschke, L. Steder DESY, Hamburg, Germany
	The AMTF (Accelerator Module Test Facility) in DESY was built for the tests of all superconducting cavities and cryomodules for the EuXFEL linac. After successful commissioning of the EuXFEL, the AMTF has been adapted in order to perform SRF (super conducting radio frequency) measurements of cavities and accelerating modules for different projects. Several SRF cavities related projects are still ongoing, while other were just finished. Some of those projects are dedicated to test components for the infrastructure of accelerators which are under construction, while the other ones are devoted to new R&D paths aiming for cavities and modules with high performance which are under investigation at DESY. This paper describes present activities performed at AMTF with special emphasis on performing SRF measurements for the ongoing cavities production. Most of the presented data is related to vertical cryostat cavity testing. However, some data about cryomodules and a new coupler test stand will be shown as well. Detailed statistics about the number of vertical tests performed within the last two years are also presented.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB058
About •	Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 02 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB075	Provision of High Beta Cavities for European Spallation Source by UKRI-STFC Daresbury Laboratory	286
	A.E. Wheelhouse, A.E.T. Akintola, A.J. Blackett-May, M.J. Ellis, S. Hitchen, P.C. Hornickel, C.R. Jenkins, P.A. McIntosh, K.J. Middleman, S.M. Pattalwar, M.D. Pendleton, J.O.W. Poynton, I.M. Skachko, P.A. Smith, S. Wilde STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom M. Lowe, D.A. Mason, G. Miller, J. Mutch, A. Oates, N. Templeton, J.T.G. Wilson STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom D. Reschke, L. Steder, M. Wiencek DESY, Hamburg, Germany
	As part of the requirement for the European Spallation Source (ESS) facility in Lund, Sweden, a project has been undertaken by Accelerator Science and Technology Cen-tre (ASTeC) as part of a UK In Kind Contribution to pro-vide 84 704 MHz High-Beta superconducting RF cavities. The project has included the procurement of niobium and the testing of cavities at Daresbury Laboratory and Deutsches Elektronen-Synchrotron (DESY), in prepara-tion for integration into the cryomodules which is being performed at Commissariat à l¿Energie Atomique et aux Energies Alternatives (CEA) Saclay, France. To date all the cavities have been manufactured in industry apart from the final cavity and 3 cavities remain to be tested. An overview of the experiences for the provision of these cavities is described.
	Poster MOPMB075 [1.428 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB075
About •	Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 08 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB082	SRF Accelerating Modules Upgrade for Flash Linac at DESY	306
	D. Kostin, S. Barbanotti, J. Eschke, K. Jensch, N. Krupka, A. Muhs, D. Reschke, S. Saegebarth, J. Schaffran, P. Schilling, M. Schmökel, L. Steder, N. Steinhau-Kühl, A. Sulimov, E. Vogel, H. Weise, M. Wiencek, B. van der Horst DESY, Hamburg, Germany
	SRF accelerating modules with 8 TESLA-type 1.3 GHz SRF cavities are the main part of the linear accelerators currently in user operation at DESY, FLASH [1, 2] and the European XFEL [3, 4]. For the FLASH upgrade in 2022 [5] two accelerating modules have been exchanged in order to enhance the beam energy to 1.3 GeV. The two modules have been prototype modules for the European XFEL. After reassembly both modules were successfully tested and installed in the FLASH linac. Data taken during the commissioning at the end of 2022 did confirm the test results. This paper presents described efforts and their conclusions since last two years and continues the presentation given at SRF 2021 [6].
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB082
About •	Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 27 June 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB037	Refurbishment and Reactivation of a Niobium Retort Furnace at DESY	485
	L. Trelle, C. Bate, H. Remde, D. Reschke, J. Schaffran, L. Steder, H. Weise DESY, Hamburg, Germany
	Funding: This work was supported by the Helmholtz Association within the topic Accelerator Research and Development (ARD) of the Matter and Technologies (MT) Program. For research in the field of heat treatments of supercon-ducting cavities, a niobium ultra-high vacuum furnace built in 1992 - originally used for the titanization of 1.3 GHz nine-cell cavities - and later shut down was recently refurbished and reactivated. A significant upgrade is the ability to run the furnace in partial pressure mode with nitrogen. The furnace is connected directly to the ISO4 area of the clean room for cavity handling. At room temperature vacuum values of around 3×10^-8 mbar are achieved. The revision included the replacement of the complete control system and a partial renewal of the pump technology. The internal mounting structures are optimized for single-cell operation including tandem operation (two single-cell cavities at once) and corresponding accessories such as witness-samples and caps for the cavities. The installation of additional thermocouples for a detailed monitoring of the temperature curves is also possible at the mounting structure. Due to the furnace design, its location and the strict routines in handling, very high purity levels are achieved in comparison to similar setups and hence provide a mighty tool for SRF cavity R&D at DESY.
	Poster TUPTB037 [0.404 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB037
About •	Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 01 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWB065	Impact of Medium Temperature Heat Treatments on the Magnetic Flux Expulsion Behavior of SRF Cavities	731
SUSPB043	use link to see paper's listing under its alternate paper code
	J.C. Wolff, J. Eschke, A. Gössel, K. Kasprzak, D. Reschke, L. Steder, L. Trelle, M. Wiencek DESY, Hamburg, Germany W. Hillert University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	Funding: This work was supported by the Helmholtz Association within the topic Accelerator Research and Development (ARD) of the Matter and Technologies (MT) Program. Medium temperature (mid-T) heat treatments at 300 °C are used to enhance the intrinsic quality factor of superconducting radio frequency (SRF) cavities. Unfortunately, such treatments potentially increase the sensitivity to trapped magnetic flux and consequently the surface resistance of the cavity. For this reason, it is crucial to maximize the expulsion of magnetic flux during the cool down. The flux expulsion behavior is next to the heat treatment mainly determined by the geometry, the niobium grain size and the grain orientation. However, it is also affected by parameters of the cavity performance tests like the cool down velocity, the spatial temperature gradient along the cavity surface and the magnetic flux density during the transition of the critical temperature. To improve the flux expulsion behavior and hence the efficiency of future accelerator facilities, the impact of these adjustable parameters as well as the mid-T heat treatment on 1.3 GHz TESLA-Type single-cell cavities is investigated by a new approach of a magnetometric mapping system. In this contribution first performance test results of cavities before- and after mid-T heat treatment are presented.
	Poster WEPWB065 [3.077 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB065
About •	Received ※ 21 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)

THCAA02	Commissioning of the UHH Quadrupole Resonator at DESY	952
SUSPB045	use link to see paper's listing under its alternate paper code
WEPWB074	use link to see paper's listing under its alternate paper code
	R. Monroy-Villa, W. Hillert, M. Wenskat University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany A. Gössel, D. Reschke, M. Röhling, M. Schmökel, J.H. Thie, M. Wiencek DESY, Hamburg, Germany C. Martens University of Hamburg, Hamburg, Germany
	Funding: This work was supported by the BMBF under the research grants 05H18GURB1, 05K19GUB and 05H2021. Pushing the limits of the accelerating field or quality factor of SRF cavities beyond pure Nb requires the implementation of specific inner surface treatments, which are yet to be studied and optimized. One of the fundamental challenges in exploring alternative materials is that only samples or cavity cuts can be fully characterized from a material point of view. On the other hand, complete cavities allow for the SRF characterization of the inner surface, while samples can usually only be analyzed using DC methods. To address this problem, a test resonator for samples, called "Quadrupole Resonator", was designed and operated at CERN and later at HZB. It allows for a full RF characterization of samples at frequencies of 0.42 GHz, 0.86 GHz, and 1.3 GHz, within a temperature range of 2-20 K and at magnetic fields up to 120 mT. This work presents the design process, which incorporated improvements motivated by mechanical and RF studies and experience, and the results from both warm and cold commissioning are discussed. More important, the results for the RF tests of a Nb sample after undergoing a series of heat treatments and an outlook of the further usage of the QPR is presented.
	Slides THCAA02 [6.677 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-THCAA02
About •	Received ※ 25 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 19 August 2023 — Issue date ※ 19 August 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

MOPMB021

Correlating Lambda Shift Measurements with RF Performance in Mid-T Heat Treated Cavities

124

SUSPB010

use link to see paper's listing under its alternate paper code

R. Ghanbari, G.K. Deyu, W. Hillert, R. Monroy-Villa, M. Wenskat
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
C. Bate, D. Reschke, L. Steder, J.C. Wolff
DESY, Hamburg, Germany

Funding: This work was supported by the BMBF under the research grants 05K19GUB and 05H2021.
Heat treatment procedures have been identified as cru-cial for the performance of niobium SRF cavities, which are the key technology of modern accelerators. The so called "mid-T heat treatments", invert the dependence of losses on the applied accelerating field (anti-Q slope) and significantly reduce the absolute value of losses. The mechanism behind these improvements is still under investigation, and further research is needed to fully understand the principle processes involved. Anomalies in the frequency shift near the transition temperature (Tc), known as "dip" can provide insight into fundamental material properties and allow us to study the relation-ship of frequency response with surface treatments. Therefore, we have measured the frequency versus temperature of multiple mid-T heat treated cavities with different recipes and studied the correlation of SRF properties with frequency shift features. The maximum quality factor correlates with two such shift features, namely the dip magnitude per temperature width and the total frequency shift.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB021

About •

Received ※ 20 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 15 August 2023

Cite •

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

MOPMB022

Recent mid-T Single-Cell Treatments R&D at DESY

129

C. Bate, D. Reschke, J. Schaffran, L. Steder, L. Trelle, H. Weise
DESY, Hamburg, Germany

The challenge of improving the performance of SRF cavities is being faced worldwide. One approach is to modify the superconducting surface properties through certain baking procedures. Recently a niobium retort furnace placed directly under an ISO4 clean room has been refurbished at DESY. Thanks to an inter-vacuum chamber and cryopumps, with high purity values in the mass spectrum it is working in the UHV range of 2·10^-8 mbar. The medium temperature (mid-T) heat treatments around 300°C are promising and successfully deliver reproducible very high Q₀ values of 2-5·10¹⁰ at medium field strengths of 16 MV/m. Since the first DESY and ZRI mid-T campaign yielded promising results, further results of 1.3 GHz single-cell cavities are presented here after several modified treatments of the mid-T recipe. In addition, samples were added to each treatment, the RRR value change was examined, and surface analyses were subsequently performed. The main focus of the sample study is the precise role of the changes in the concentration of impurities on the surface. In particular, the change in oxygen content due to diffusion processes is suspected to be the cause of enhancing the performance.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB022

About •

Received ※ 18 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 01 July 2023

Cite •

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

MOPMB058

Summary of the Superconducting Rf Measurements in AMTF Hall at DESY

248

M. Wiencek, K. Kasprzak, D. Kostin, D. Reschke, L. Steder
DESY, Hamburg, Germany

The AMTF (Accelerator Module Test Facility) in DESY was built for the tests of all superconducting cavities and cryomodules for the EuXFEL linac. After successful commissioning of the EuXFEL, the AMTF has been adapted in order to perform SRF (super conducting radio frequency) measurements of cavities and accelerating modules for different projects. Several SRF cavities related projects are still ongoing, while other were just finished. Some of those projects are dedicated to test components for the infrastructure of accelerators which are under construction, while the other ones are devoted to new R&D paths aiming for cavities and modules with high performance which are under investigation at DESY. This paper describes present activities performed at AMTF with special emphasis on performing SRF measurements for the ongoing cavities production. Most of the presented data is related to vertical cryostat cavity testing. However, some data about cryomodules and a new coupler test stand will be shown as well. Detailed statistics about the number of vertical tests performed within the last two years are also presented.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB058

About •

Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 02 July 2023

Cite •

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

MOPMB075

Provision of High Beta Cavities for European Spallation Source by UKRI-STFC Daresbury Laboratory

286

A.E. Wheelhouse, A.E.T. Akintola, A.J. Blackett-May, M.J. Ellis, S. Hitchen, P.C. Hornickel, C.R. Jenkins, P.A. McIntosh, K.J. Middleman, S.M. Pattalwar, M.D. Pendleton, J.O.W. Poynton, I.M. Skachko, P.A. Smith, S. Wilde
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
M. Lowe, D.A. Mason, G. Miller, J. Mutch, A. Oates, N. Templeton, J.T.G. Wilson
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
D. Reschke, L. Steder, M. Wiencek
DESY, Hamburg, Germany

As part of the requirement for the European Spallation Source (ESS) facility in Lund, Sweden, a project has been undertaken by Accelerator Science and Technology Cen-tre (ASTeC) as part of a UK In Kind Contribution to pro-vide 84 704 MHz High-Beta superconducting RF cavities. The project has included the procurement of niobium and the testing of cavities at Daresbury Laboratory and Deutsches Elektronen-Synchrotron (DESY), in prepara-tion for integration into the cryomodules which is being performed at Commissariat à l¿Energie Atomique et aux Energies Alternatives (CEA) Saclay, France. To date all the cavities have been manufactured in industry apart from the final cavity and 3 cavities remain to be tested. An overview of the experiences for the provision of these cavities is described.

Poster MOPMB075 [1.428 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB075

About •

Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 08 July 2023

Cite •

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

MOPMB082

SRF Accelerating Modules Upgrade for Flash Linac at DESY

306

D. Kostin, S. Barbanotti, J. Eschke, K. Jensch, N. Krupka, A. Muhs, D. Reschke, S. Saegebarth, J. Schaffran, P. Schilling, M. Schmökel, L. Steder, N. Steinhau-Kühl, A. Sulimov, E. Vogel, H. Weise, M. Wiencek, B. van der Horst
DESY, Hamburg, Germany

SRF accelerating modules with 8 TESLA-type 1.3 GHz SRF cavities are the main part of the linear accelerators currently in user operation at DESY, FLASH [1, 2] and the European XFEL [3, 4]. For the FLASH upgrade in 2022 [5] two accelerating modules have been exchanged in order to enhance the beam energy to 1.3 GeV. The two modules have been prototype modules for the European XFEL. After reassembly both modules were successfully tested and installed in the FLASH linac. Data taken during the commissioning at the end of 2022 did confirm the test results. This paper presents described efforts and their conclusions since last two years and continues the presentation given at SRF 2021 [6].

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB082

About •

Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 27 June 2023

Cite •

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

TUPTB037

Refurbishment and Reactivation of a Niobium Retort Furnace at DESY

485

L. Trelle, C. Bate, H. Remde, D. Reschke, J. Schaffran, L. Steder, H. Weise
DESY, Hamburg, Germany

Funding: This work was supported by the Helmholtz Association within the topic Accelerator Research and Development (ARD) of the Matter and Technologies (MT) Program.
For research in the field of heat treatments of supercon-ducting cavities, a niobium ultra-high vacuum furnace built in 1992 - originally used for the titanization of 1.3 GHz nine-cell cavities - and later shut down was recently refurbished and reactivated. A significant upgrade is the ability to run the furnace in partial pressure mode with nitrogen. The furnace is connected directly to the ISO4 area of the clean room for cavity handling. At room temperature vacuum values of around 3×10^-8 mbar are achieved. The revision included the replacement of the complete control system and a partial renewal of the pump technology. The internal mounting structures are optimized for single-cell operation including tandem operation (two single-cell cavities at once) and corresponding accessories such as witness-samples and caps for the cavities. The installation of additional thermocouples for a detailed monitoring of the temperature curves is also possible at the mounting structure. Due to the furnace design, its location and the strict routines in handling, very high purity levels are achieved in comparison to similar setups and hence provide a mighty tool for SRF cavity R&D at DESY.

Poster TUPTB037 [0.404 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB037

About •

Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 01 July 2023

Cite •

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

WEPWB065

Impact of Medium Temperature Heat Treatments on the Magnetic Flux Expulsion Behavior of SRF Cavities

731

SUSPB043

use link to see paper's listing under its alternate paper code

J.C. Wolff, J. Eschke, A. Gössel, K. Kasprzak, D. Reschke, L. Steder, L. Trelle, M. Wiencek
DESY, Hamburg, Germany
W. Hillert
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

Funding: This work was supported by the Helmholtz Association within the topic Accelerator Research and Development (ARD) of the Matter and Technologies (MT) Program.
Medium temperature (mid-T) heat treatments at 300 °C are used to enhance the intrinsic quality factor of superconducting radio frequency (SRF) cavities. Unfortunately, such treatments potentially increase the sensitivity to trapped magnetic flux and consequently the surface resistance of the cavity. For this reason, it is crucial to maximize the expulsion of magnetic flux during the cool down. The flux expulsion behavior is next to the heat treatment mainly determined by the geometry, the niobium grain size and the grain orientation. However, it is also affected by parameters of the cavity performance tests like the cool down velocity, the spatial temperature gradient along the cavity surface and the magnetic flux density during the transition of the critical temperature. To improve the flux expulsion behavior and hence the efficiency of future accelerator facilities, the impact of these adjustable parameters as well as the mid-T heat treatment on 1.3 GHz TESLA-Type single-cell cavities is investigated by a new approach of a magnetometric mapping system. In this contribution first performance test results of cavities before- and after mid-T heat treatment are presented.

Poster WEPWB065 [3.077 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB065

About •

Received ※ 21 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)

THCAA02

Commissioning of the UHH Quadrupole Resonator at DESY

952

SUSPB045

use link to see paper's listing under its alternate paper code

WEPWB074

use link to see paper's listing under its alternate paper code

R. Monroy-Villa, W. Hillert, M. Wenskat
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
A. Gössel, D. Reschke, M. Röhling, M. Schmökel, J.H. Thie, M. Wiencek
DESY, Hamburg, Germany
C. Martens
University of Hamburg, Hamburg, Germany

Funding: This work was supported by the BMBF under the research grants 05H18GURB1, 05K19GUB and 05H2021.
Pushing the limits of the accelerating field or quality factor of SRF cavities beyond pure Nb requires the implementation of specific inner surface treatments, which are yet to be studied and optimized. One of the fundamental challenges in exploring alternative materials is that only samples or cavity cuts can be fully characterized from a material point of view. On the other hand, complete cavities allow for the SRF characterization of the inner surface, while samples can usually only be analyzed using DC methods. To address this problem, a test resonator for samples, called "Quadrupole Resonator", was designed and operated at CERN and later at HZB. It allows for a full RF characterization of samples at frequencies of 0.42 GHz, 0.86 GHz, and 1.3 GHz, within a temperature range of 2-20 K and at magnetic fields up to 120 mT. This work presents the design process, which incorporated improvements motivated by mechanical and RF studies and experience, and the results from both warm and cold commissioning are discussed. More important, the results for the RF tests of a Nb sample after undergoing a series of heat treatments and an outlook of the further usage of the QPR is presented.

Slides THCAA02 [6.677 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-THCAA02

About •

Received ※ 25 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 19 August 2023 — Issue date ※ 19 August 2023

Cite •

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