SRF2023 - List of Authors (Rosaz, G.J.)

Paper	Title	Page
MOPMB003	Flux Expulsion Lens: Concept and Measurements	56
	D.A. Turner European Organization for Nuclear Research (CERN), Geneva, Switzerland A. Gallifa Terricabras, T. Koettig, A. Macpherson, G.J. Rosaz, N. Stapley CERN, Meyrin, Switzerland I. González Díaz-Palacio University of Hamburg, Hamburg, Germany W. Hillert University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany M. Wenskat DESY, Hamburg, Germany
	A magnetic flux expulsion lens (MFEL) has been designed and built at CERN. This device uses closed topology conduction cooling of samples to quantify magnetic flux expulsion of superconductors, and allows for systematic measurements of the cooling dynamics and the magnetic response during the superconducting transition. Measurements for bulk Nb, cold worked Nb, sputtered Nb on Cu, and SIS multilayer structures are given. Preliminary results for both sample characterization of expulsion dynamics, and observation of an enhanced flux expulsion in SIS samples are also reported.
	Poster MOPMB003 [2.459 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB003
About •	Received ※ 27 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 14 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEIXA02	Results of the R&D RF Testing Campaign of 1.3 GHz Nb/Cu Cavities	621
	L. Vega Cid, S. Atieh, G. Bellini, A. Bianchi, L.M.A. Ferreira, C. Pereira Carlos, G.J. Rosaz, W. Venturini Delsolaro CERN, Meyrin, Switzerland S.B. Leith European Organization for Nuclear Research (CERN), Geneva, Switzerland
	In the context of the R&D program on Nb/Cu carried out at CERN, a total of 25 tests have been performed since 2021. This talk will present these results. Three different manufacturing techniques have been used to produce the copper substrates, in order to investigate which is the most suitable in terms of quality and economy of scale. On one hand, the focus has been on optimizing the surface resistance at 4.2K, as this will be the operating temperature of FCC. The results at this temperature are encouraging, showing repeatable and optimized RF performance. On the other hand, RF tests have been done at 1.85 K too aiming at deepening the knowledge of the mechanisms behind the Q slope. This is key to work on the mitigation of this phenomenon and ultimately to extend the application of this technology to high energy, high gradient accelerators. The influence of the thermal cycles has been thoroughly investigated. A systematic improvement has been observed of both the Q slope and the residual resistance with slow thermal cycles.
	Slides WEIXA02 [5.385 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEIXA02
About •	Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 02 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Flux Expulsion Lens: Concept and Measurements

56

D.A. Turner
European Organization for Nuclear Research (CERN), Geneva, Switzerland
A. Gallifa Terricabras, T. Koettig, A. Macpherson, G.J. Rosaz, N. Stapley
CERN, Meyrin, Switzerland
I. González Díaz-Palacio
University of Hamburg, Hamburg, Germany
W. Hillert
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
M. Wenskat
DESY, Hamburg, Germany

A magnetic flux expulsion lens (MFEL) has been designed and built at CERN. This device uses closed topology conduction cooling of samples to quantify magnetic flux expulsion of superconductors, and allows for systematic measurements of the cooling dynamics and the magnetic response during the superconducting transition. Measurements for bulk Nb, cold worked Nb, sputtered Nb on Cu, and SIS multilayer structures are given. Preliminary results for both sample characterization of expulsion dynamics, and observation of an enhanced flux expulsion in SIS samples are also reported.

Poster MOPMB003 [2.459 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB003

About •

Received ※ 27 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 14 July 2023

Cite •

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

WEIXA02

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

621

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

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

Slides WEIXA02 [5.385 MB]

DOI •

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

About •

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

Cite •

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