CERN Accelerating science

Published Articles
Title	Simulation and Measurements of Crab Cavity HOMs and HOM Couplers for HL-LHC
Author(s)	Mitchell, James (Lancaster U. (main) ; CERN ; Cockcroft Inst. Accel. Sci. Tech.) ; Apsimon, Robert (Lancaster U. (main) ; Cockcroft Inst. Accel. Sci. Tech.) ; Ben-Zvi, Ilan (Brookhaven Natl. Lab.) ; Burt, Graeme (Lancaster U. (main) ; Cockcroft Inst. Accel. Sci. Tech.) ; Calaga, Rama (CERN) ; Castilla, Alejandro (CERN) ; Jones, Thomas (Lancaster U. (main) ; Cockcroft Inst. Accel. Sci. Tech.) ; Macpherson, Alick (CERN) ; Powers, Tom (Jefferson Lab) ; Shipman, Nicholas (Lancaster U. (main) ; CERN ; Cockcroft Inst. Accel. Sci. Tech.) ; Verdú-Andrés, Silvia (Brookhaven Natl. Lab.) ; Wang, Haipeng (Jefferson Lab) ; Xiao, Binping (Brookhaven Natl. Lab.) ; Zwozniak, Agnieszka (CERN)
Publication	2018
Number of pages	5
In:	18th International Conference on RF Superconductivity, Lanzhou, China, 17 - 21 Jul 2017, pp.THPB059
DOI	10.18429/JACoW-SRF2017-THPB059
Subject category	Accelerators and Storage Rings
Project	CERN HL-LHC
Abstract	Two Superconducting Radio-Frequency (SRF) crab cavities are foreseen for the High Luminosity LHC (HL-LHC) upgrade. Preliminary beam tests of the Double Quarter Wave (DQW) crab cavity will take place in the Super Proton Synchrotron (SPS) in 2018. For damping of the cavity's Higher Order Modes (HOMs) the DQW has three identical on-cell, superconducting HOM couplers. The couplers are actively cooled by liquid heluim. In this paper, electromagnetic simulations of the HOMs and HOM couplers are presented. A novel approach to pre-installation spectral analysis of the HOM couplers is then presented, detailing both simulated and measured data. Measurements of the cavity HOMs at warm and in Vertical Test Facilities (VTFs) at both JLAB and CERN are detailed, comparing the measured characteristics of each mode to that of the simulated data-sets. Finally, the measured cavity data is compared with the test box measurements to see by what extent any reduction in damping can be predicted.
Copyright/License	CC-BY-3.0

Corresponding record in: Inspire