arXiv : Transverse Beam Stability with Low-Impedance Collimators in the High Luminosity Large Hadron Collider: Status and Challenges

Antipov, S.A.; Biancacci, N.; Redaelli, S.; Carideo, E.; Valuch, D.; Salvant, B.; Mereghetti, A.; Métral, E.; Amorim, D.

doi:10.1103/PhysRevAccelBeams.23.034403

Article
Report number	arXiv:1910.09974
Title	Transverse Beam Stability with Low-Impedance Collimators in the High Luminosity Large Hadron Collider: Status and Challenges
Author(s)	Antipov, S.A. (CERN) ; Amorim, D. (CERN) ; Biancacci, N. (CERN) ; Carideo, E. (CERN) ; Mereghetti, A. (CERN) ; Métral, E. (CERN) ; Redaelli, S. (CERN) ; Salvant, B. (CERN) ; Valuch, D. (CERN)
Publication	2020-03-30
Imprint	2019-10-22
Number of pages	13
In:	Phys. Rev. Accel. Beams 23 (2020) 034403
DOI	10.1103/PhysRevAccelBeams.23.034403
Subject category	physics.acc-ph ; Accelerators and Storage Rings
Abstract	The High-Luminosity upgrade of the Large Hadron Collider (HL-LHC) will double its beam intensity for the needs of High Energy Physics frontier. In order to ensure coherent stability until the beams are put in collision, the transverse impedance has to be reduced. As the major portion of the ring impedance is sup
Copyright/License	preprint: (License: arXiv nonexclusive-distrib 1.0) publication: © 2020-2025 authors (License: CC-BY-4.0)

$Schematics of the LHC Run II collimation layout (prior to 2019)~\citep{bib:w2}.$ $LHC collimators dominate the overall machine impedance at the top energy (plotted on the left -- real part of the dipolar impedance as a function of frequency). They are responsible for nearly all the octupole current required to stabilize the beam, with $\sim50$\% coming from 11 secondary betatron cleaning collimators (plotted on the right -- estimated octupole threshold with a factor$