MOPS138

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URL	https://doi.org/10.18429/JACoW-IPAC2025-MOPS138
Title	Simulation of machine-induced background to ALICE in the 2023 LHC ion run
Authors	H. Guerin, A. Ferrero Colomo, A. Lechner, F. Cerutti, L. Esposito, M. Danisch, R. Bruce, R. Cai, V. Rodin European Organization for Nuclear Research C. Oppedisano Istituto Nazionale di Fisica Nucleare, Sezione di Torino F. Andrea Commissariat à l'Énergie Atomique et aux Énergies Alternatives J. Otwinowski Institute of Nuclear Physics, Polish Academy of Sciences P. Kurashvili National Centre for Nuclear Research
Abstract	During the 2023 ion run at the LHC, where crystal collimation was regularly adopted for the first time, strong background levels were observed at the Inner Tracking System (ITS) of the ALICE detector. Some of the readout chips became saturated, causing losses of angular acceptance. This background was mitigated using a dispersion knob in the beam optics, letting some residual background remain. Considering that the next upgrade of the ALICE ITS foresees a further reduction of the interaction chamber aperture, understanding the mechanisms leading to this background appears critical to envision appropriated mitigation solutions. Preliminary studies showed that this background was related to losses at the upstream tertiary collimator (TCT), impacted by 207Pb82+ ions issued from beam interaction with the crystals of the primary collimation stage. Based on FLUKA simulations, this paper investigates the propagation of the tertiary collimator showers towards the ALICE cavern.
Paper	download: MOPS138.pdf
Cite	BibTeX, LaTeX, Text/Word, RIS, EndNote
Conference	16th International Particle Accelerator Conference
Series
Location	Taipei, Taiwan
Date	01-06 Jun 2025
Publisher	JACoW Publishing, Geneva, Switzerland
Editorial Board	* Ming-Chyuan Lin - National Synchrotron Radiation Research Center * Yoichi Sato - KEK * Jui-Che Huang - National Synchrotron Radiation Research Center * David Button - Australian Nuclear Science and Technology Organisation * Ping-Shun Chuang - National Synchrotron Radiation Research Center
Online ISBN	978-3-95450-248-6
Online ISSN	2673-5490
Received	27 May 2025
Revised	04 June 2025
Accepted	04 June 2025
Issued	05 November 2025
DOI	10.18429/JACoW-IPAC2025-MOPS138
Pages	825-828
Copyright	Published by JACoW Publishing under the terms of the Creative Commons Attribution 4.0 license. Any further distribution of this work must maintain attribution to the author(s), the published article's title, publisher, and DOI.