Author: Lindstrom, B.    [Lindström, B.]
Paper Title Page
TUPOTK062 Settings for Improved Betatron Collimation in the First Run of the High Luminosity LHC 1366
 
  • B. Lindström, A. Abramov, R. Bruce, R. De Maria, P.D. Hermes, J. Molson, S. Redaelli, F.F. Van der Veken
    CERN, Meyrin, Switzerland
 
  Funding: This work was supported by the High Luminosity LHC project
The current betatron collimation system in the LHC is not optimized to absorb off-momentum particles scattered out from the primary collimators. The highest losses are concentrated in the downstream dispersion suppressor (DS). Given the increased beam intensity in the High Luminosity LHC (HL-LHC), there is concern that these losses could risk quenching the superconducting DS magnets. Consequently, a dedicated upgrade of the DS has been studied. However, at this stage, the deployment for the startup of the HL-LHC is uncertain due to delays in the availability of high-field magnets needed to integrate new collimators into the DS. In this paper, we describe the expected collimation setup for the first run of the HL-LHC and explore various techniques to improve the collimation cleaning. These include exploiting the asymmetric response of the two jaws of each primary collimator and adjusting the locally generated dispersion in the collimation insertion.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK062  
About • Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 23 June 2022
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WEPOPT013 Effect of a Spurious CLIQ Firing on the Circulating Beam in HL-LHC 1862
 
  • C. Hernalsteens, B. Lindström, E. Ravaioli, O.K. Tuormaa, M. Villén Basco, C. Wiesner, D. Wollmann
    CERN, Meyrin, Switzerland
 
  The High Luminosity LHC (HL-LHC) will reach a nominal, levelled luminosity of §I{5e34}{\per\cm\square\per\second} and a stored energy of nearly §I{700}{MJ} in each of the two proton beams. The new large-aperture final focusing Nb3Sn quadrupole magnets in IR1 and IR5, which are essential to achieve the luminosity target, will be protected using the novel Coupling Loss Induced Quench (CLIQ) system. A spurious discharge of a CLIQ unit will impact the circulating beam through higher order multipolar field components that develop rapidly over a few turns. This paper reports on dedicated beam tracking studies performed to evaluate the criticality of this failure on the HL-LHC beam. Simulations for different machine and optics configurations show that the beam losses reach a critical level after only five machine turns following the spurious CLIQ trigger, which is much faster than assumed in previous simulations that did not consider the higher order multipolar fields. Machine protection requirements using a dedicated interlock to mitigate this failure are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT013  
About • Received ※ 08 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 01 July 2022  
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