SRF2021 - List of Authors (Therasse, M.)

Paper	Title	Page
WEOCAV03	RF Dipole Crab Cavity Testing for HL-LHC	687
	N. Valverde Alonso, R. Calaga, S.J. Calvo, O. Capatina, O. Capatina, A. Castilla, M. Chiodini, C. Duval, L.M.A. Ferreira, M. Gourragne, P.J. Kohler, T. Mikkola, J.A. Mitchell, E. Montesinos, C. Pasquino, G. Pechaud, N. Stapley, M. Therasse, K. Turaj, J.D. Walker CERN, Meyrin, Switzerland A. Castilla Cockcroft Institute, Lancaster University, Lancaster, United Kingdom A. Castilla Lancaster University, Lancaster, United Kingdom
	RF Crab Cavities are an essential element of the High Luminosity LHC (HL-LHC) upgrade at CERN. Two RF dipole crab cavity used for the compensation of the horizontal crossing angle were recently manufactured and integrated into Titanium Helium tank and RF ancillaries necessary for the beam operation. The two cavities will be integrated into a cryomodule in collaboration with UK-STFC and tested with proton beams in the SPS in 2023. This paper will highlight the RF measurements during the important manufacturing steps, surface preparation and cavity performance at 2K.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-WEOCAV03
About •	Received ※ 18 June 2021 — Revised ※ 07 September 2021 — Accepted ※ 16 September 2021 — Issue date ※ 22 November 2021
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPFAV006	Degradation and Recovery of the LHC RF Cryomodule Performance Using the Helium Processing Technique	746
	K. Turaj, O. Brunner, A.C. Butterworth, F. Gerigk, P. Maesen, E. Montesinos, F. Peauger, M. Therasse, W. Venturini Delsolaro CERN, Meyrin, Switzerland
	The LHC RF cryomodule "Asia" suffered an accidental influx of about 0.5 l of tunnel air during the leak checks of the pumping manifolds. The resulting risk of particle contamination was difficult to assess, and could not be excluded with certainty. If one or more cavities were contaminated, a severe impact on beam operations in the LHC machine was to be expected. In order to minimize the risks, the Asia cryomodule has been replaced with a spare unit. Subsequently, the cryomodule was tested in the SM18 test facility without intermediate venting, and showed high levels of radiation due to field emission above 1.8 MV in one of the cavities. The other cavities were less strongly affected, but clear signs of contamination were observed. The helium processing technique was used to improve the performance of the SRF cavity with respect to field emission. This paper will discuss the results of the above-mentioned test.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPFAV006
About •	Received ※ 21 June 2021 — Revised ※ 14 January 2022 — Accepted ※ 27 April 2022 — Issue date ※ 01 May 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

RF Dipole Crab Cavity Testing for HL-LHC

687

N. Valverde Alonso, R. Calaga, S.J. Calvo, O. Capatina, O. Capatina, A. Castilla, M. Chiodini, C. Duval, L.M.A. Ferreira, M. Gourragne, P.J. Kohler, T. Mikkola, J.A. Mitchell, E. Montesinos, C. Pasquino, G. Pechaud, N. Stapley, M. Therasse, K. Turaj, J.D. Walker
CERN, Meyrin, Switzerland
A. Castilla
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
A. Castilla
Lancaster University, Lancaster, United Kingdom

RF Crab Cavities are an essential element of the High Luminosity LHC (HL-LHC) upgrade at CERN. Two RF dipole crab cavity used for the compensation of the horizontal crossing angle were recently manufactured and integrated into Titanium Helium tank and RF ancillaries necessary for the beam operation. The two cavities will be integrated into a cryomodule in collaboration with UK-STFC and tested with proton beams in the SPS in 2023. This paper will highlight the RF measurements during the important manufacturing steps, surface preparation and cavity performance at 2K.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-WEOCAV03

About •

Received ※ 18 June 2021 — Revised ※ 07 September 2021 — Accepted ※ 16 September 2021 — Issue date ※ 22 November 2021

Cite •

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

THPFAV006

Degradation and Recovery of the LHC RF Cryomodule Performance Using the Helium Processing Technique

746

K. Turaj, O. Brunner, A.C. Butterworth, F. Gerigk, P. Maesen, E. Montesinos, F. Peauger, M. Therasse, W. Venturini Delsolaro
CERN, Meyrin, Switzerland

The LHC RF cryomodule "Asia" suffered an accidental influx of about 0.5 l of tunnel air during the leak checks of the pumping manifolds. The resulting risk of particle contamination was difficult to assess, and could not be excluded with certainty. If one or more cavities were contaminated, a severe impact on beam operations in the LHC machine was to be expected. In order to minimize the risks, the Asia cryomodule has been replaced with a spare unit. Subsequently, the cryomodule was tested in the SM18 test facility without intermediate venting, and showed high levels of radiation due to field emission above 1.8 MV in one of the cavities. The other cavities were less strongly affected, but clear signs of contamination were observed. The helium processing technique was used to improve the performance of the SRF cavity with respect to field emission. This paper will discuss the results of the above-mentioned test.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPFAV006

About •

Received ※ 21 June 2021 — Revised ※ 14 January 2022 — Accepted ※ 27 April 2022 — Issue date ※ 01 May 2022

Cite •

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