SRF2017 - List of Keywords (superconducting-cavity)

Paper	Title	Other Keywords	Page
MOPB062	Development of HOM Absorbers for CW Superconducting Cavities in Energy Recovery Linac	HOM, ion, cavity, linac	191
	T. Ota, A. Miyamoto, K. Sato, M. Takasaki, M. Yamada Toshiba, Yokohama, Japan E. Kako, T. Konomi, H. Sakai, K. Umemori KEK, Ibaraki, Japan
	Higher Order Modes (HOM) absorbers for superconducting cavities have been developing at TOSHIBA in collaboration with High Energy Accelerator Research Organization (KEK) since 2015. Prototype HOM absorbers for 1.3 GHz 9-cell superconducting cavity were fabricated. An AlN lossy dielectrics cylinder was brazed with a copper cylinder, and the cool-down tests by nitrogen gas was carried out. Copper cylinders and SUS flanges were joined by electron beam welding to fabricate a whole prototype HOM absorber. Fabrication process of the prototype HOM absorber will be presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB062
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TUPB082	Setup of a Spatially Resolving Vector Magnetometry System for the Investigation of Flux Trapping in Superconducting Cavities	ion, cavity, SRF, niobium	580
	B. Schmitz, K. Alomari, J. Knobloch, O. Kugeler, J.M. Köszegi, Y. Tamashevich HZB, Berlin, Germany
	Flux trapping is the major contribution to the residual resistance of superconducting cavities. In order to gain a better understanding of the mechanisms involved and aiming at an eventual minimization of trapped flux, a measurement setup based on AMR sensors was devised that allows for monitoring the magnetic field vector at various positions near the cavity surface. First results of the efforts are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB082
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THXA04	Fabrication, Treatment and Test of Large Grain Cavities	cavity, ion, SRF, FEL	700
	J.K. Hao, J.E. Chen, L.W. Feng, L. Lin, K.X. Liu, S.W. Quan, F. Wang, H.M. Xie, F. Zhu PKU, Beijing, People's Republic of China
	Development of SRF technology has been included in the project of Soft X-ray FEL (SXFEL) for a hard X-ray FEL plan in China which would be operated in CW mode. Six 9-cell TESLA type cavities as well as several single-cell cavities made of Ningxia large grain niobium material have been fabricated by Peking University for achieving high gradient and high intrinsic quality factor Q0. The measurements of gradient and Q0 have been carried out with a new vertical test system at PKU. The process of fabrication, surface treatment and test results of these large grain cavities will be presented.
	Slides THXA04 [7.911 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THXA04
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THPB003	An Innovative Design of a Flexible Temperature-mapping System	cavity, ion, SRF, electron	746
	M. Ge, F. Furuta, M. Liepe, P.J. Pamel Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	A temperature-mapping (T-Map) system is an essential tool for fundamental SRF research as it provides spatial information of RF power dissipation and so allows localizing hot-spots on a cavity surface at cryogenic temperatures. However, the temperature sensors are mounted on rigid boards in most current systems, so each can only work for one specific cavity size and shape. In this paper, we proposed a flexible design, which allows this temperature mapping system to work for different cavity shapes.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THPB003
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THPB004	Impact of the Duration of Low Temperature Doping on Superconducting Cavity Performance	cavity, ion, niobium, vacuum	750
	P.N. Koufalis, F. Furuta, J.J. Kaufman, M. Liepe Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Low temperature treatments of superconducting cavities in a low pressure ambient atmosphere have been shown to introduce a 'Q-rise' up to moderate surface fields and an overall increase in quality factor. However, the effect of varying the doping time at a fixed temperature on cavity performance has not been systematically examined. We present results of such an investigation for cavities prepared at 120 and 160 C in a continuously flowing low pressure atmosphere for various amounts of time. We show that the introduction of impurities to the RF penetration layer can improve cavity performance and investigate the relationship between electron mean free path and the temperature-dependent component of the surface resistance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THPB004
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THPB028	Flux Pinning Study of OTIC Niobium Material	ion, niobium, site, cavity	797
	S. Chen, J.K. Hao, L. Lin, K.X. Liu, S.W. Quan PKU, Beijing, People's Republic of China
	The performance of superconducting cavities is influenced by the trapped flux during the cooling down through critical temperature, especially for nitrogen doped cavities which are more sensitive to flux trapping. We have investigated the flux trapping of OTIC niobium samples with different grain size. Samples were prepared and heat treated at 800°C and 900°C, followed with different surface removal by BCP. A series of measurements, including MPMS, TOF-SIMS, were carried out on the niobium samples. The results and analysis will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THPB028
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Paper

Title

Other Keywords

Page

MOPB062

Development of HOM Absorbers for CW Superconducting Cavities in Energy Recovery Linac

HOM, ion, cavity, linac

191

T. Ota, A. Miyamoto, K. Sato, M. Takasaki, M. Yamada
Toshiba, Yokohama, Japan
E. Kako, T. Konomi, H. Sakai, K. Umemori
KEK, Ibaraki, Japan

Higher Order Modes (HOM) absorbers for superconducting cavities have been developing at TOSHIBA in collaboration with High Energy Accelerator Research Organization (KEK) since 2015. Prototype HOM absorbers for 1.3 GHz 9-cell superconducting cavity were fabricated. An AlN lossy dielectrics cylinder was brazed with a copper cylinder, and the cool-down tests by nitrogen gas was carried out. Copper cylinders and SUS flanges were joined by electron beam welding to fabricate a whole prototype HOM absorber. Fabrication process of the prototype HOM absorber will be presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB062

Export •

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

TUPB082

Setup of a Spatially Resolving Vector Magnetometry System for the Investigation of Flux Trapping in Superconducting Cavities

ion, cavity, SRF, niobium

580

B. Schmitz, K. Alomari, J. Knobloch, O. Kugeler, J.M. Köszegi, Y. Tamashevich
HZB, Berlin, Germany

Flux trapping is the major contribution to the residual resistance of superconducting cavities. In order to gain a better understanding of the mechanisms involved and aiming at an eventual minimization of trapped flux, a measurement setup based on AMR sensors was devised that allows for monitoring the magnetic field vector at various positions near the cavity surface. First results of the efforts are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB082

Export •

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

THXA04

Fabrication, Treatment and Test of Large Grain Cavities

cavity, ion, SRF, FEL

700

J.K. Hao, J.E. Chen, L.W. Feng, L. Lin, K.X. Liu, S.W. Quan, F. Wang, H.M. Xie, F. Zhu
PKU, Beijing, People's Republic of China

Development of SRF technology has been included in the project of Soft X-ray FEL (SXFEL) for a hard X-ray FEL plan in China which would be operated in CW mode. Six 9-cell TESLA type cavities as well as several single-cell cavities made of Ningxia large grain niobium material have been fabricated by Peking University for achieving high gradient and high intrinsic quality factor Q0. The measurements of gradient and Q0 have been carried out with a new vertical test system at PKU. The process of fabrication, surface treatment and test results of these large grain cavities will be presented.

Slides THXA04 [7.911 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THXA04

Export •

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

THPB003

An Innovative Design of a Flexible Temperature-mapping System

cavity, ion, SRF, electron

746

M. Ge, F. Furuta, M. Liepe, P.J. Pamel
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

A temperature-mapping (T-Map) system is an essential tool for fundamental SRF research as it provides spatial information of RF power dissipation and so allows localizing hot-spots on a cavity surface at cryogenic temperatures. However, the temperature sensors are mounted on rigid boards in most current systems, so each can only work for one specific cavity size and shape. In this paper, we proposed a flexible design, which allows this temperature mapping system to work for different cavity shapes.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THPB003

Export •

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

THPB004

Impact of the Duration of Low Temperature Doping on Superconducting Cavity Performance

cavity, ion, niobium, vacuum

750

P.N. Koufalis, F. Furuta, J.J. Kaufman, M. Liepe
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Low temperature treatments of superconducting cavities in a low pressure ambient atmosphere have been shown to introduce a 'Q-rise' up to moderate surface fields and an overall increase in quality factor. However, the effect of varying the doping time at a fixed temperature on cavity performance has not been systematically examined. We present results of such an investigation for cavities prepared at 120 and 160 C in a continuously flowing low pressure atmosphere for various amounts of time. We show that the introduction of impurities to the RF penetration layer can improve cavity performance and investigate the relationship between electron mean free path and the temperature-dependent component of the surface resistance.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THPB004

Export •

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

THPB028

Flux Pinning Study of OTIC Niobium Material

ion, niobium, site, cavity

797

S. Chen, J.K. Hao, L. Lin, K.X. Liu, S.W. Quan
PKU, Beijing, People's Republic of China

The performance of superconducting cavities is influenced by the trapped flux during the cooling down through critical temperature, especially for nitrogen doped cavities which are more sensitive to flux trapping. We have investigated the flux trapping of OTIC niobium samples with different grain size. Samples were prepared and heat treated at 800°C and 900°C, followed with different surface removal by BCP. A series of measurements, including MPMS, TOF-SIMS, were carried out on the niobium samples. The results and analysis will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THPB028

Export •

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