CERN Accelerating science

Article
Title	Collimator Scan Based Beam Halo Measurements in LHC and HL-LHC
Author(s)	Hermes, Pascal (CERN) ; Giovannozzi, Massimo (CERN) ; Montanari, Carlo Emilio (CERN ; U. Manchester (main)) ; Morales Vigo, Sara (CERN ; Cockcroft Inst. Accel. Sci. Tech.) ; Rakic, Milica (Ecole Polytechnique, Lausanne) ; Redaelli, Stefano (CERN) ; Salvachúa, Belen (CERN)
Publication	2023
Number of pages	5
In:	JACoW IBIC 2023 (2023) 164-168
In:	12th International Beam Instrumentation Conference (IBIC 2023), Saskatoon, Canada, 10 - 14 Sep 2023, pp.164-168
DOI	10.18429/JACoW-IBIC2023-TU3C03
Subject category	Accelerators and Storage Rings
Abstract	Measurements in the CERN Large Hadron Collider (LHC) have indicated that the population of the transverse beam halo is greater than that of a Gaussian distribution. With the upcoming High Luminosity upgrade (HL-LHC), the stored beam energy in the beam halo could become large enough to threaten the integrity of the collimation system. Considerable efforts during the ongoing LHC Run 3 are dedicated to characterising the transverse beam halo, and its diffusion properties, after the LHC Injector Upgrade (LIU) in preparation for HL-LHC operation. Given the unprecedented stored beam energies of about 400MJ, presently achieved at the LHC, and about 700MJ planned at the HL-LHC, conventional measurements are difficult. Halo and diffusion measurements are currently based on collimator scans, where robust collimators are inserted in steps into the circulating beam halo. In this contribution, we present techniques for halo characterisation employed in LHC and compare results obtained from such measurements in LHC Run 2 and the ongoing LHC Run 3. We present plans for measurements in the remainder of LHC Run 3 and describe expected challenges for halo quantification in HL-LHC.
Copyright/License	© 2024 the author(s) (License: CC-BY-4.0)

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