SRF2023 - List of Authors (Kugeler, O.)

Paper	Title	Page
MOPMB010	Analysis of Semiconductor Components as Temperature Sensors for Cryogenic Investigation of SRF Materials	80
SUSPB006	use link to see paper's listing under its alternate paper code
	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)

TUCXA01	Study of the Dynamics of Flux Trapping in Different SRF Materials	380
	F. Kramer, S. Keckert, J. Knobloch, O. Kugeler HZB, Berlin, Germany J. Knobloch University of Siegen, Siegen, Germany T. Kubo KEK, Ibaraki, Japan
	A dedicated experimental setup to measure magnetic flux dynamics and trapped flux in samples is used to precisely map out how trapped flux is influenced by different parameters. The setup allows for rapid thermal cycling of the sample so that effects of cooldown parameters can be investigated in detail. We show how temperature gradient, cooldown rate, and the magnitude of external field influence trapped flux in large grain, fine grain and coated niobium samples. The detailed measurements show unexpected results, namely that too fast cooldowns increase trapped flux, large grain material traps flux only when the external field is larger than a temperature gradient dependent threshold field, and the measured dependence of trapped flux on temperature gradient does not agree with an existing model. Therefore, a new model is presented which agrees better with the measured results.
	Slides TUCXA01 [3.180 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUCXA01
About •	Received ※ 17 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 26 June 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB002	Modelling Trapped Flux in Niobium	393
SUSPB017	use link to see paper's listing under its alternate paper code
	F. Kramer, S. Keckert, J. Knobloch, O. Kugeler HZB, Berlin, Germany J. Knobloch University of Siegen, Siegen, Germany T. Kubo KEK, Ibaraki, Japan
	Detailed measurements of magnetic flux dynamics and trapped magnetic flux in niobium samples were conducted with a new experimental setup that permits precise control of the cooldown parameters. With this setup the dependency of trapped flux on the temperature gradient, external magnetic field, and cooldown rate can be mapped out in more detail compared to cavity measurements. We have obtained unexpected results, and an existing model describing trapped flux in dependence of temperature gradient does not agree with the measured data. Therefore, a new model is developed which describes the magnitude of trapped flux in dependence of the temperature gradient across the sample during cooldown. The model describes the amount of trapped flux lines with help of a density distribution function of the pinning forces of pinning centers and the thermal force which can de-pin flux lines from pinning centers. The model shows good agreement with the measured data and correctly predicts trapped flux at different external flux densities.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB002
About •	Received ※ 17 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 13 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

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

WECAA01	Progress in European Thin Film Activities	607
	C. Pira, O. Azzolini, R. Caforio, E. Chyhyrynets, D. Fonnesu, D. Ford, V.A. Garcia, G. Keppel, G. Marconato, A. Salmaso, F. Stivanello INFN/LNL, Legnaro (PD), Italy C.Z. Antoine, Y. Kalboussi, Th. Proslier CEA-IRFU, Gif-sur-Yvette, France C. Benjamin, O.B. Malyshev, N. Marks, B.S. Sian, R. Valizadeh STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom C. Benjamin, J.W. Bradley, G. Burt, O.B. Malyshev, N. Marks, D.J. Seal, B.S. Sian, S. Simon, D.A. Turner, R. Valizadeh Cockcroft Institute, Warrington, Cheshire, United Kingdom S. Berry CEA-DRF-IRFU, France R. Berton, D. Piccoli, F. Piccoli, G. Squizzato, F. Telatin Piccoli, Noale (VE), Italy M. Bertucci, R. Paparella INFN/LASA, Segrate (MI), Italy M. Bonesso, S. Candela, V. Candela, R. Dima, G. Favero, A. Pepato, P. Rebesan, M. Romanato INFN- Sez. di Padova, Padova, Italy J.W. Bradley, S. Simon The University of Liverpool, Liverpool, United Kingdom G. Burt, D.J. Seal, D.A. Turner Lancaster University, Lancaster, United Kingdom O. Hryhorenko, D. Longuevergne Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France X. Jiang, T. Staedler, A.O. Zubtsovskii University Siegen, Siegen, Germany S. Keckert, J. Knobloch, O. Kugeler HZB, Berlin, Germany J. Knobloch University of Siegen, Siegen, Germany N.L. Leicester Cockcroft Institute, Lancaster University, Lancaster, United Kingdom A. Medvids, A. Mychko, P. Onufrijevs Riga Technical University, Riga, Latvia S. Prucnal, S. Zhou HZDR, Dresden, Germany R. Ries Slovak Academy of Sciences, Institute of Electrical Engineering, Bratislava, Slovak Republic E. Seiler IEE, Bratislava, Slovak Republic L.G.P. Smith STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom A-M. Valente-Feliciano JLab, Newport News, Virginia, USA
	Funding: This project has received funding from the European Union s Horizon 2020 Research and Innovation programme under Grant Agreement No 101004730. Thin-film cavities with higher Tc superconductors (SC) than Nb promise to move the operating temperature from 2 to 4.5 K with savings 3 orders of magnitude in cryogenic power consumption. Several European labs are coordinating their efforts to obtain a first 1.3 GHz cavity prototype through the I.FAST collaboration and other informal collaborations with CERN and DESY. R&D covers the entire production chain. In particular, new production techniques of seamless Copper and Niobium elliptical cavities via additive manufacturing are studied and evaluated. New acid-free polishing techniques to reduce surface roughness in a more sustainable way such as plasma electropolishing and metallographic polishing have been tested. Optimization of coating parameters of higher Tc SC than Nb (Nb₃Sn, V₃Si, NbTiN) via PVD and multilayer via ALD are on the way. Finally, rapid heat treatments such as Flash Lamp Annealing and Laser Annealing are used to avoid or reduce Cu diffusion in the SC film. The development and characterization of SC coatings is done on planar samples, 6 GHz cavities, choke cavities, QPR and 1.3 GHz cavities. This work presents the progress status of these coordinated efforts.
	Slides WECAA01 [15.846 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WECAA01
About •	Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 02 September 2023 — Issue date ※ 02 September 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEIXA06	Recent Advances in Metallographic Polishing for SRF Application	646
	O. Hryhorenko JLab, Newport News, Virginia, USA C.Z. Antoine, F. Éozénou, Th. Proslier Université Paris-Saclay, CEA, Gif-sur-Yvette, France T. Dohmae KEK, Ibaraki, Japan S. Keckert, J. Knobloch, O. Kugeler HZB, Berlin, Germany D. Longuevergne Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
	Funding: ENSAR-2 under grant agreement N° 654002. IFAST under Grant Agreement No 101004730. The U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177. This talk is an overview of the metallographic polishing R&D program covering Niobium and Copper substrates treatment for thin film coating as an alternative fabrication pathway for 1.3 GHz elliptical cavities. The presented research is the result of a collaborative effort between IJCLab, CEA/Irfu, HZB, and KEK in order to develop innovative surface processing and cavity fabrication protocols capable of meeting stringent requirements for SRF surfaces, including the reduction of safety risks and ecological footprint, enhancing reliability, improving the surface roughness, and potentially allowing cost reduction. The research findings will be disclosed.
	Slides WEIXA06 [7.469 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEIXA06
About •	Received ※ 16 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 14 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

MOPMB010

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

80

SUSPB006

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

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)

TUCXA01

Study of the Dynamics of Flux Trapping in Different SRF Materials

380

F. Kramer, S. Keckert, J. Knobloch, O. Kugeler
HZB, Berlin, Germany
J. Knobloch
University of Siegen, Siegen, Germany
T. Kubo
KEK, Ibaraki, Japan

A dedicated experimental setup to measure magnetic flux dynamics and trapped flux in samples is used to precisely map out how trapped flux is influenced by different parameters. The setup allows for rapid thermal cycling of the sample so that effects of cooldown parameters can be investigated in detail. We show how temperature gradient, cooldown rate, and the magnitude of external field influence trapped flux in large grain, fine grain and coated niobium samples. The detailed measurements show unexpected results, namely that too fast cooldowns increase trapped flux, large grain material traps flux only when the external field is larger than a temperature gradient dependent threshold field, and the measured dependence of trapped flux on temperature gradient does not agree with an existing model. Therefore, a new model is presented which agrees better with the measured results.

Slides TUCXA01 [3.180 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUCXA01

About •

Received ※ 17 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 26 June 2023

Cite •

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

TUPTB002

Modelling Trapped Flux in Niobium

393

SUSPB017

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

F. Kramer, S. Keckert, J. Knobloch, O. Kugeler
HZB, Berlin, Germany
J. Knobloch
University of Siegen, Siegen, Germany
T. Kubo
KEK, Ibaraki, Japan

Detailed measurements of magnetic flux dynamics and trapped magnetic flux in niobium samples were conducted with a new experimental setup that permits precise control of the cooldown parameters. With this setup the dependency of trapped flux on the temperature gradient, external magnetic field, and cooldown rate can be mapped out in more detail compared to cavity measurements. We have obtained unexpected results, and an existing model describing trapped flux in dependence of temperature gradient does not agree with the measured data. Therefore, a new model is developed which describes the magnitude of trapped flux in dependence of the temperature gradient across the sample during cooldown. The model describes the amount of trapped flux lines with help of a density distribution function of the pinning forces of pinning centers and the thermal force which can de-pin flux lines from pinning centers. The model shows good agreement with the measured data and correctly predicts trapped flux at different external flux densities.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB002

About •

Received ※ 17 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 13 July 2023

Cite •

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

TUPTB013

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

410

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

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

Poster TUPTB013 [0.464 MB]

DOI •

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

About •

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

Cite •

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

WECAA01

Progress in European Thin Film Activities

607

C. Pira, O. Azzolini, R. Caforio, E. Chyhyrynets, D. Fonnesu, D. Ford, V.A. Garcia, G. Keppel, G. Marconato, A. Salmaso, F. Stivanello
INFN/LNL, Legnaro (PD), Italy
C.Z. Antoine, Y. Kalboussi, Th. Proslier
CEA-IRFU, Gif-sur-Yvette, France
C. Benjamin, O.B. Malyshev, N. Marks, B.S. Sian, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
C. Benjamin, J.W. Bradley, G. Burt, O.B. Malyshev, N. Marks, D.J. Seal, B.S. Sian, S. Simon, D.A. Turner, R. Valizadeh
Cockcroft Institute, Warrington, Cheshire, United Kingdom
S. Berry
CEA-DRF-IRFU, France
R. Berton, D. Piccoli, F. Piccoli, G. Squizzato, F. Telatin
Piccoli, Noale (VE), Italy
M. Bertucci, R. Paparella
INFN/LASA, Segrate (MI), Italy
M. Bonesso, S. Candela, V. Candela, R. Dima, G. Favero, A. Pepato, P. Rebesan, M. Romanato
INFN- Sez. di Padova, Padova, Italy
J.W. Bradley, S. Simon
The University of Liverpool, Liverpool, United Kingdom
G. Burt, D.J. Seal, D.A. Turner
Lancaster University, Lancaster, United Kingdom
O. Hryhorenko, D. Longuevergne
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
X. Jiang, T. Staedler, A.O. Zubtsovskii
University Siegen, Siegen, Germany
S. Keckert, J. Knobloch, O. Kugeler
HZB, Berlin, Germany
J. Knobloch
University of Siegen, Siegen, Germany
N.L. Leicester
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
A. Medvids, A. Mychko, P. Onufrijevs
Riga Technical University, Riga, Latvia
S. Prucnal, S. Zhou
HZDR, Dresden, Germany
R. Ries
Slovak Academy of Sciences, Institute of Electrical Engineering, Bratislava, Slovak Republic
E. Seiler
IEE, Bratislava, Slovak Republic
L.G.P. Smith
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
A-M. Valente-Feliciano
JLab, Newport News, Virginia, USA

Funding: This project has received funding from the European Union s Horizon 2020 Research and Innovation programme under Grant Agreement No 101004730.
Thin-film cavities with higher Tc superconductors (SC) than Nb promise to move the operating temperature from 2 to 4.5 K with savings 3 orders of magnitude in cryogenic power consumption. Several European labs are coordinating their efforts to obtain a first 1.3 GHz cavity prototype through the I.FAST collaboration and other informal collaborations with CERN and DESY. R&D covers the entire production chain. In particular, new production techniques of seamless Copper and Niobium elliptical cavities via additive manufacturing are studied and evaluated. New acid-free polishing techniques to reduce surface roughness in a more sustainable way such as plasma electropolishing and metallographic polishing have been tested. Optimization of coating parameters of higher Tc SC than Nb (Nb₃Sn, V₃Si, NbTiN) via PVD and multilayer via ALD are on the way. Finally, rapid heat treatments such as Flash Lamp Annealing and Laser Annealing are used to avoid or reduce Cu diffusion in the SC film. The development and characterization of SC coatings is done on planar samples, 6 GHz cavities, choke cavities, QPR and 1.3 GHz cavities. This work presents the progress status of these coordinated efforts.

Slides WECAA01 [15.846 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WECAA01

About •

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

Cite •

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

WEIXA06

Recent Advances in Metallographic Polishing for SRF Application

646

O. Hryhorenko
JLab, Newport News, Virginia, USA
C.Z. Antoine, F. Éozénou, Th. Proslier
Université Paris-Saclay, CEA, Gif-sur-Yvette, France
T. Dohmae
KEK, Ibaraki, Japan
S. Keckert, J. Knobloch, O. Kugeler
HZB, Berlin, Germany
D. Longuevergne
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France

Funding: ENSAR-2 under grant agreement N° 654002. IFAST under Grant Agreement No 101004730. The U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
This talk is an overview of the metallographic polishing R&D program covering Niobium and Copper substrates treatment for thin film coating as an alternative fabrication pathway for 1.3 GHz elliptical cavities. The presented research is the result of a collaborative effort between IJCLab, CEA/Irfu, HZB, and KEK in order to develop innovative surface processing and cavity fabrication protocols capable of meeting stringent requirements for SRF surfaces, including the reduction of safety risks and ecological footprint, enhancing reliability, improving the surface roughness, and potentially allowing cost reduction. The research findings will be disclosed.

Slides WEIXA06 [7.469 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEIXA06

About •

Received ※ 16 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 14 July 2023

Cite •

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