CERN Accelerating science

Article
Title	Operational handling of Crystal collimation at the LHC
Author(s)	Mirarchi, D (CERN) ; Andreassen, O (CERN) ; Bruce, R (CERN) ; Cai, R (CERN ; Ecole Polytechnique, Lausanne) ; Di Castro, M (CERN) ; D'Andrea, M (CERN) ; Hostettler, M (CERN) ; Jacquet, D (CERN) ; Masi, A (CERN) ; Matheson, E (CERN) ; Redaelli, S (CERN) ; Ricci, G (CERN ; Rome U.) ; Solfaroli, M (CERN) ; Solis, S (CERN) ; Tagg, J (CERN) ; Wenninger, J (CERN)
Publication	2023
Number of pages	4
In:	JACoW IPAC 2023 (2023) MOPL022
In:	14th International Particle Accelerator Conference (IPAC 2023), Venice, Italy, 7 - 12 May 2023, pp.MOPL022
DOI	10.18429/JACoW-IPAC2023-MOPL022
Subject category	Accelerators and Storage Rings
Abstract	A non-negligible risk of magnet quenches occurring due to the reduced cleaning performance of the original LHC collimation system with lead ion beams was expected at an energy of 6.8 Z TeV beams. Crystal collimation has therefore been integrated into the HL-LHC upgrade baseline to overcome present limitations. The upgrade scope involves the installation of 4 new crystal primary collimators. Upgraded devices were installed based on the experience and experimental evidence gathered with a previously-installed test stand. In preparation to the new operational challenges, the controls of the new devices were integrated in the high-level LHC collimation control system, which is used to orchestrate the operation of these devices in harmony with all the other components of the machine. A dedicated application was also developed to address three main tasks: to find the main planar channeling of newly installed crystals using Machine Learning models developed at CERN; to optimise the angular orientation to maximise the channeling efficiency; to monitor that the optimal channeling orientation is kept throughout the fill. This paper will present and discuss all of these aspects.
Copyright/License	CC-BY-4.0

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