CERN Accelerating science

Article
Title	Beam coupling impedance of the main extraction kickers in the CERN PS
Author(s)	Neroni, M (CERN ; U. Rome La Sapienza (main)) ; Barnes, M J (CERN) ; Lasheen, A (CERN) ; Mostacci, A (U. Rome La Sapienza (main)) ; Popovic, B (Argonne) ; Vollinger, C (CERN)
Publication	2024
Number of pages	12
In:	JINST 19 (2024) T08001
In:	68th ICFA Advanced Beam Dynamics workshop on high-Intensity and High-Brightness Hadron Beams (HB 2023), CERN, Geneva, Switzerland, 9 - 13 Oct 2023, pp.T08001
DOI	10.1088/1748-0221/19/08/T08001
Subject category	Accelerators and Storage Rings
Accelerator/Facility, Experiment	CERN PS
Abstract	In view of the High Luminosity (HL) upgrade of the LHC, thebeam intensity must be doubled in the injector chain. To performreliable beam dynamics simulations, the beam coupling impedance inthe injectors, such as the Proton Synchrotron (PS), must be followedclosely by including all contributing elements into the impedancemodel. The existing kicker magnets of the PS had been optimized forlarge kick strength and short rise/fall times, but not necessarilyto minimise beam coupling impedance. Hence, unwanted beam inducedvoltage can build up in their electrical circuits, with an impact onthe beam. The beam coupling impedances of the two main kickermagnets used for the fast extraction from PS, the KFA71 and KFA79,are extensively characterized in this study. In particular,electromagnetic simulation results for the longitudinal andtransverse coupling impedance are shown. The critical impedancecontributions are identified, and their effect on beam stabilitywith a possible mitigation solution is discussed. Moreover, theimpact of the cable terminations on the electromagnetic fieldpattern and possible mitigation techniques are presented, providinga complete impedance evaluation of the entire kicker installation.
Copyright/License	CC-BY-4.0 publication: © 2024 The authors

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