IPAC2021 - List of Authors (Caspers, F.)

Paper	Title	Page
MOPAB364	Shielded Pair Method for Cylindrical Surface Resistance Measurement at Cryogenic Temperature	1132
	K. Brunner, S. Calatroni, F. Caspers CERN, Geneva, Switzerland D. Barna Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary
	The shielded pair resonator method was already used in the past at CERN to measure the surface resistivity of the LHC beam screen both at room temperature and cryogenic temperature. We have refined and adapted the measurement to be able to measure other types of beam screens and also to operate in a strong dipolar magnetic field. This is necessary for testing the properties of HTS coated beam screens or the possible effects of coatings and surface treatments for e-cloud suppression. Several calibration runs were done at cryogenic temperatures (4.2 K) measuring the surface resistivity of a copper pipe to identify the precision, stability and reproducibility achievable using this method. This work describes the challenges of the measurement and ways to mitigate them.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB364
About •	paper received ※ 17 May 2021 paper accepted ※ 22 June 2021 issue date ※ 12 August 2021
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THPAB235	Detailed Electromagnetic Characterisation of HL-LHC Low Impedance Collimators	4258
	A. Kurtulus, C. Accentura, N. Biancacci, F. Carra, F. Caspers, N. Chitnis, F. Giordano, R. Illan Fiastre, S. Joly, I. Lamas Garcia, L. Mourier, E. Métral, S. Redaelli, B. Salvant, W. Vollenberg, C. Vollinger, C. Zannini CERN, Geneva, Switzerland
	The High Luminosity Large Hadron Collider (HL-LHC) project will upgrade the LHC machine to allow operation with increased luminosity for the experiments. In order to achieve this goal, different operational parameters of the machine need to be pushed beyond the present design values, including the stored beam energy. One of the main challenges related to the achievement of the upgraded performance is the beam collimation system and its contribution to the overall machine impedance budget. In this perspective, new low impedance collimators have been designed, fabricated, and installed in the LHC. In this study, we will present their detailed electromagnetic (EM) characterization by means of radio frequency (RF) measurements and EM simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB235
About •	paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 10 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Shielded Pair Method for Cylindrical Surface Resistance Measurement at Cryogenic Temperature

1132

K. Brunner, S. Calatroni, F. Caspers
CERN, Geneva, Switzerland
D. Barna
Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary

The shielded pair resonator method was already used in the past at CERN to measure the surface resistivity of the LHC beam screen both at room temperature and cryogenic temperature. We have refined and adapted the measurement to be able to measure other types of beam screens and also to operate in a strong dipolar magnetic field. This is necessary for testing the properties of HTS coated beam screens or the possible effects of coatings and surface treatments for e-cloud suppression. Several calibration runs were done at cryogenic temperatures (4.2 K) measuring the surface resistivity of a copper pipe to identify the precision, stability and reproducibility achievable using this method. This work describes the challenges of the measurement and ways to mitigate them.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB364

About •

paper received ※ 17 May 2021 paper accepted ※ 22 June 2021 issue date ※ 12 August 2021

Export •

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

THPAB235

Detailed Electromagnetic Characterisation of HL-LHC Low Impedance Collimators

4258

A. Kurtulus, C. Accentura, N. Biancacci, F. Carra, F. Caspers, N. Chitnis, F. Giordano, R. Illan Fiastre, S. Joly, I. Lamas Garcia, L. Mourier, E. Métral, S. Redaelli, B. Salvant, W. Vollenberg, C. Vollinger, C. Zannini
CERN, Geneva, Switzerland

The High Luminosity Large Hadron Collider (HL-LHC) project will upgrade the LHC machine to allow operation with increased luminosity for the experiments. In order to achieve this goal, different operational parameters of the machine need to be pushed beyond the present design values, including the stored beam energy. One of the main challenges related to the achievement of the upgraded performance is the beam collimation system and its contribution to the overall machine impedance budget. In this perspective, new low impedance collimators have been designed, fabricated, and installed in the LHC. In this study, we will present their detailed electromagnetic (EM) characterization by means of radio frequency (RF) measurements and EM simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB235

About •

paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 10 August 2021

Export •

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