MC1: Circular and Linear Colliders
T19 Collimation
Paper Title Page
MOPAB002 Risk of Halo-Induced Magnet Quenches in the HL-LHC Beam Dump Insertion 41
 
  • J.B. Potoine, A. Apollonio, E. Belli, C. Bracco, R. Bruce, M. D’Andrea, R. García Alía, A. Lechner, G. Lerner, S. Morales Vigo, S. Redaelli, V. Rizzoglio, E. Skordis, A. Waets
    CERN, Meyrin, Switzerland
  • F. Wrobel
    IES, Montpellier, France
 
  Funding: Research supported by the HL-LHC project
After the High Luminosity (HL-LHC) upgrade, the LHC will be exposed to a higher risk of magnet quenches during periods of short beam lifetime. Collimators in the extraction region (IR6) assure the protection of magnets against asynchronous beam dumps, but they also intercept a fraction of the beam halo leaking from the betatron cleaning insertion. In this paper, we assess the risk of quenching nearby quadrupoles during beam lifetime drops. In particular, we present an empirical analysis of halo losses in IR6 using LHC Run 2 (2015-2018) beam loss monitor measurements. Based on these results, the halo-induced power density in magnet coils expected in HL-LHC is estimated using FLUKA Monte Carlo shower simulations.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB002  
About • paper received ※ 19 May 2021       paper accepted ※ 13 July 2021       issue date ※ 22 August 2021  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPAB006 Optics Configurations for Improved Machine Impedance and Cleaning Performance of a Multi-Stage Collimation Insertion 57
 
  • R. Bruce, R. De Maria, M. Giovannozzi, N. Mounet, S. Redaelli
    CERN, Geneva, Switzerland
 
  For a two-stage collimation system, the betatron phase advance between the primary and secondary stages is usually set to maximise the absorption of secondary particles outscattered from the primary. Another constraint is the contribution to the ring impedance of the collimation system, which can be decreased through an optimized insertion optics, featuring large values of the beta functions. In this article we report on first studies of such an optics for the CERN LHC. In addition to a gain in impedance, we show that the cleaning efficiency can be improved thanks to the large beta functions, even though the phase advance is not set at the theoretical optimum.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB006  
About • paper received ※ 17 May 2021       paper accepted ※ 28 May 2021       issue date ※ 11 August 2021  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPAB023 Crystal Collimation of 20 MJ Heavy-Ion Beams at the HL-LHC 2644
 
  • M. D’Andrea, R. Bruce, M. Di Castro, I. Lamas Garcia, A. Masi, D. Mirarchi, S. Redaelli, R. Rossi, B. Salvachua, W. Scandale
    CERN, Geneva, Switzerland
  • F. Galluccio
    INFN-Napoli, Napoli, Italy
  • L.J. Nevay
    Royal Holloway, University of London, Surrey, United Kingdom
 
  The concept of crystal collimation at the Large Hadron Collider (LHC) relies on the use of bent crystals that can deflect halo particles by a much larger angle than the standard multi-stage collimation system. Following an extensive campaign of studies and performance validations, a number of crystal collimation tests with Pb ion beams were performed in 2018 at energies up to 6.37 Z TeV. This paper describes the procedure and outcomes of these tests, the most important of which being the demonstration of the capability of crystal collimation to improve the cleaning efficiency of the machine. These results led to the inclusion of crystal collimation into the LHC baseline for operation with ion beams in Run 3 as well as for the HL-LHC era. A first set of operational settings was defined.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB023  
About • paper received ※ 19 May 2021       paper accepted ※ 23 June 2021       issue date ※ 27 August 2021  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPAB025 Collimation Strategies for Secondary Beams in FCC-hh Ion-Ion Operation 2652
 
  • J.R. Hunt, R. Bruce, F. Carra, F. Cerutti, J. Guardia, J. Molson
    CERN, Geneva, Switzerland
 
  The target peak luminosity of the CERN FCC-hh during Pb-Pb collisions is more than a factor of 50 greater than that achieved by the LHC in 2018. As a result, the intensity of secondary beams produced in collisions at the interaction points will be significantly higher than previously experienced. With up to 72 kW deposited in a localised region by a single secondary beam type, namely the one originated by Bound Free Pair Production (BFPP), it is essential to develop strategies to safely intercept these beams, including the ones from ElectroMagnetic Dissociation (EMD), in order to ensure successful FCC-hh Pb-Pb operation. A series of beam tracking and energy deposition simulations were performed to determine the optimal solution for handling the impact of such beams. In this contribution the most advanced results are presented, with a discussion of different options.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB025  
About • paper received ※ 18 May 2021       paper accepted ※ 02 July 2021       issue date ※ 18 August 2021  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)