Author: Bruce, R.
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MOPOST045 A Novel Tool for Beam Dynamics Studies with Hollow Electron Lenses 176
 
  • P.D. Hermes, R. Bruce, R. De Maria, M. Giovannozzi, G. Iadarola, D. Mirarchi, S. Redaelli
    CERN, Meyrin, Switzerland
 
  Hollow Electron Lenses (HELs) are crucial components of the CERN LHC High Luminosity Upgrade (HL-LHC), serving the purpose of actively controlling the population of the transverse beam halo to reduce particle losses on the collimation system. Symplectic particle tracking simulations are required to optimize the efficiency and study potentially undesired beam dynamics effects with the HELs. With the relevant time scales in the collider in the order of several minutes, tracking simulations require considerable computing resources. A new tracking tool, Xsuite, developed at CERN since 2021, offers the possibility of performing such tracking simulations using graphics processing units (GPUs), with promising perspectives for the simulation of hadron beam dynamics with HELs. In this contribution, we present the implementation of HEL physics effects in the new tracking framework. We compare the performance with previous tools and show simulation results obtained using known and newly established simulation setups.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST045  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 08 July 2022
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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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WEPOST016 Development of Collimation Simulations for the FCC-ee 1718
 
  • A. Abramov, R. Bruce, M. Hofer, G. Iadarola, S. Redaelli
    CERN, Meyrin, Switzerland
  • F.S. Carlier, T. Pieloni, M. Rakic
    EPFL, Lausanne, Switzerland
  • L.J. Nevay
    JAI, Egham, Surrey, United Kingdom
  • S.M. White
    ESRF, Grenoble, France
 
  A collimation system is under study for the FCC-ee to protect the machine from the multi-MJ electron and positron beams and limit the backgrounds to the detectors. One of the key aspects of the collimation system design is the setup of simulation studies combining particle tracking and scattering in the collimators. The tracking must include effects important for electron beam single-particle dynamics in the FCC-ee, such as synchrotron radiation. For collimation, an aperture model and particle-matter interactions for electrons are required. There are currently no established simulation frameworks that include all the required features. The latest developments of an integrated framework for multi-turn collimation studies in the FCC-ee are presented. The framework is based on an interface between tracking codes, pyAT and Xtrack, and a particle-matter interaction code, BDSIM, based on Geant4. Promising alternative simulation codes and frameworks are also discussed. The challenges are outlined, and the first results are presented, including preliminary loss maps for the FCC-ee.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST016  
About • Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 29 June 2022
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WEPOST017 Design of a Collimation Section for the FCC-ee 1722
 
  • M. Hofer, A. Abramov, R. Bruce, K. Oide, F. Zimmermann
    CERN, Meyrin, Switzerland
  • M. Moudgalya, T. Pieloni
    EPFL, Lausanne, Switzerland
  • K. Oide
    KEK, Ibaraki, Japan
 
  The design parameters of the FCC-ee foresee operation with a total stored beam energy of about 20 MJ, exceeding those of previous lepton colliders by almost two orders of magnitude. Given the inherent damage potential, a halo collimation system is studied to protect the machine hardware, in particular superconducting equipment such as the final focus quadrupoles, from sudden beam loss. The different constraints that led to dedicating one straight section to collimation will be outlined. In addition, a preliminary layout and optics for a collimation insertion are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST017  
About • Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 25 June 2022
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WEPOST018 Power Deposition Studies for Crystal-Based Heavy Ion Collimation in the LHC 1726
SUSPMF007   use link to see paper's listing under its alternate paper code  
 
  • J.B. Potoine, R. Bruce, R. Cai, L.S. Esposito, P.D. Hermes, A. Lechner, S. Redaelli, A. Waets
    CERN, Meyrin, Switzerland
  • F. Wrobel
    IES, Montpellier, France
 
  The LHC heavy-ion program with 208Pb82+ beams is foreseen to benefit from a significant intensity upgrade in 2022. A performance limitation may arise from ion fragments scattered out of the collimators in the betatron cleaning insertion, which risk quenching superconducting magnets during periods of short beam lifetime. In order to mitigate this risk, an alternative collimation technique, relying on bent crystals as primary collimators, will be used in future heavy-ion runs. In this paper, we study the power deposition in superconducting magnets by means of FLUKA shower simulations, comparing the standard collimation system against the crystal-based one. The studies focus on the dispersion suppressor regions downstream of the betatron cleaning insertion, where the ion fragment losses are the highest. Based on these studies, we quantify the expected quench margin expected in future runs with 208Pb82+ beams.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST018  
About • Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 03 July 2022
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WEPOST019 Benchmarks of Energy Deposition Studies for Heavy-Ion Collimation Losses at the LHC 1730
 
  • J.B. Potoine, R. Bruce, R. Cai, P.D. Hermes, A. Lechner, S. Redaelli, A. Waets
    CERN, Meyrin, Switzerland
  • F. Wrobel
    IES, Montpellier, France
 
  During some periods in its second physics run (2015-2018), the LHC has been operated with 208Pb82+ ion beams at an energy of 6.37 ZTeV. The LHC is equipped with a betatron collimation system, which intercepts the transverse beam halo and protects sensitive equipment such as superconducting magnets against beam losses. However, hadronic fragmentation and electromagnetic dissociation of heavy ions in collimators generate off-rigidity particles, which can be lost in the downstream dispersion suppressor, putting the magnets at risk to quench. An accurate modelling of the beam-induced energy deposition in the collimation system and superconducting magnets is important for quantifying possible performance limitations arising from magnet quenches. In this paper, we compare FLUKA shower simulations against beam loss monitor measurements recorded during the 2018 208Pb82+ run. In particular, we investigate fast beam loss events, which lead to recurring beam aborts in 2018 operation. Based on these studies, we assess the ability of the simulation model to reproduce the observed loss patterns in the collimation region and dispersion suppressor.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST019  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 23 June 2022
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WEPOPT009 Operational Scenario of First High Luminosity LHC Run 1846
 
  • R. Tomás García, G. Arduini, P. Baudrenghien, R. Bruce, O.S. Brüning, X. Buffat, R. Calaga, F. Cerutti, R. De Maria, J. Dilly, I. Efthymiopoulos, M. Giovannozzi, P.D. Hermes, G. Iadarola, O.R. Jones, S. Kostoglou, E.H. Maclean, N. Mounet, E. Métral, Y. Papaphilippou, S. Redaelli, G. Sterbini, H. Timko, F.F. Van der Veken, J. Wenninger, M. Zerlauth
    CERN, Meyrin, Switzerland
 
  A new scenario for the first operational run of the HL-LHC era (Run 4) has been recently developed to accommodate a period of performance ramp-up to achieve an annual integrated luminosity close to the nominal HL-LHC design. The operational scenario in terms of beam parameters and machine settings, as well as the different phases, are described here along with the impact of potential delays on key hardware components.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT009  
About • Received ※ 19 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 09 July 2022
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WEPOTK018 Simulation of Heavy-Ion Beam Losses with Crystal Collimation* 2082
SUSPMF048   use link to see paper's listing under its alternate paper code  
 
  • R. Cai, R. Bruce, R. Bruce, M. D’Andrea, L.S. Esposito, P.D. Hermes, A. Lechner, A. Lechner, D. Mirarchi, J.B. Potoine, S. Redaelli, F. Salvat Pujol, J. Schoofs
    CERN, Meyrin, Switzerland
  • J.B. Potoine
    IES, Montpellier, France
  • M. Seidel
    PSI, Villigen PSI, Switzerland
 
  With the higher stored energy envisioned for future heavy-ion runs in the LHC and the challenging fragmentation aspect of heavy-ion beams due to interaction with collimator material, the need arises for even more performing collimation systems. One promising solution is crystal channeling, which is used in the HL-LHC baseline and starts with Run III for heavy-ion collimation. To investigate an optimal configuration for the collimation system, a well-tested simulation setup is required. This work shows the simulations of channeling and other coherent effects in the SixTrack-FLUKA Coupling simulation framework and compares simulated loss patterns with data from previous beam tests.
*Research supported by the HL’LHC project
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK018  
About • Received ※ 07 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 15 June 2022  
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WEPOTK034 LHC Beam Collimation During Extended β*-Levelling in Run 3 2138
 
  • F.F. Van der Veken, R. Bruce, M. Hostettler, D. Mirarchi, S. Redaelli
    CERN, Meyrin, Switzerland
 
  During the third operational Run of the Large Hadron Collider at CERN, starting in 2022, the bunch population will be increased to unprecedented levels requiring to deploy β*-levelling of the luminosity over a wide range of values to cope with the limitations imposed by event pile-up at the experiments and heat load on the triplets induced by collision debris. During this levelling, both beam optics and orbit change in various areas of the ring, in particular around the high-luminosity experiments, where several collimators are installed. This requires adapting the collimation system settings adequately, in particular for the tertiary collimators (TCTs) that protect the inner-triplet magnets. To this end, two strategies are considered: keeping collimators at fixed physical openings while shifting their centres following the beam orbit, or varying also the collimator openings. The latter strategy is planned when the larger optics range will be deployed. In this paper, we investigate several loss scenarios at the TCTs in different steps of the levelling, and present the proposed collimator settings during Run 3.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK034  
About • Received ※ 07 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 07 July 2022  
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