Keyword: collimation
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TUC4C2 Mitigating Collimation Impedance and Improving Halo Cleaning with New Optics and Settings Strategy of the HL-LHC Betatron Collimation System optics, impedance, simulation, experiment 183
 
  • B. Lindström, R. Bruce, X. Buffat, R. De Maria, L. Giacomel, P.D. Hermes, D. Mirarchi, N. Mounet, T.H.B. Persson, S. Redaelli, R. Tomás García, F.F. Van der Veken, A. Wegscheider
    CERN, Meyrin, Switzerland
 
  Funding: Work supported by the HL-LHC project
With High Luminosity Large Hadron Collider (HL-LHC) beam intensities, there are concerns that the beam losses in the dispersion suppressors around the betatron cleaning insertion might exceed the quench limits. Furthermore, to maximize the beam lifetime it is important to reduce the impedance as much as possible. The collimators constitute one of the main sources of impedance in HL-LHC, given the need to operate with small collimator gaps. To improve this, a new optics was developed which increases the beta function in the collimation area, as well as the single pass dispersion from the primary collimators to the downstream shower absorbers. Other possible improvements from orbit bumps, to further enhance the locally generated dispersion, and from asymmetric collimator settings were also studied. The new solutions were partially tested with 6.8 TeV beams at the LHC in a dedicated machine experiment in 2022. In this paper, the new performance is reviewed and prospects for future operational deployment are discussed.
 
slides icon Slides TUC4C2 [2.222 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC4C2  
About • Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 28 October 2023
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WEC2C1 Evaluation of Power Deposition in HL-LHC with Crystal-assisted Heavy Ion Collimation heavy-ion, operation, simulation, betatron 236
 
  • V. Rodin, R. Bruce, R. Cai, M. D’Andrea, L.S. Esposito, A. Lechner, J.B. Potoine, S. Redaelli, J. Schoofs
    CERN, Meyrin, Switzerland
  • R. Cai
    EPFL, Lausanne, Switzerland
  • J.B. Potoine
    IES, Montpellier, France
 
  The future LHC heavy-ion program, utilizing 208Pb82+ beams at up to 7 Z TeV, is anticipated to operate with substantial intensity upgrade. During periods of short beam lifetime, a potential performance limitation may arise from secondary ions produced by electromagnetic dissociation and hadronic fragmentation in the collimators of the betatron cleaning insertion. These off-rigidity fragments risk quenching superconducting magnets when they are lost in the dispersion suppressor. To address this concern, an alternative collimation scheme will be introduced for forthcoming heavy ion runs, employing bent channeling crystals as primary collimators. In this contribution, we detail a thorough study of power deposition levels in superconducting magnets through FLUKA shower simulations in the crystal-based collimation system. The study focuses on the downstream dispersion suppressor regions of the betatron cleaning insertion, where the quench risk is the highest. Based on this work, we quantify the expected quench margin in future runs with 208Pb82+ beams, providing crucial insights for the successful execution of the upgraded heavy-ion program at the HL-LHC.
Research supported by the HL-LHC project.
 
slides icon Slides WEC2C1 [3.105 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC2C1  
About • Received ※ 24 November 2023 — Revised ※ 25 November 2023 — Accepted ※ 29 November 2023 — Issued ※ 16 January 2024
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WEC3C3 Simulations and Measurements of Betatron and Off-momentum Cleaning Performance in the Energy Ramp at the LHC simulation, betatron, injection, optics 279
 
  • N. Triantafyllou, R. Bruce, M. D’Andrea, K.A. Dewhurst, B. Lindström, D. Mirarchi, S. Redaelli, F.F. Van der Veken
    CERN, Meyrin, Switzerland
 
  The Large Hadron Collider (LHC) is equipped with a multistage collimation system that protects the machine against unavoidable beam losses at large betatron and energy offsets at all stages of operation. Dedicated validations and an understanding in simulations of the collimation performance are crucial for the energy ramp from 450 GeV to 6.8 TeV because complex changes of optics and orbit take place in this phase. Indeed, the betatron functions are reduced in all experiments for an efficient setup of the collisions at top energy. In this paper, simulations of the betatron and off-momentum cleaning during the energy ramp are presented. A particular focus is given to the off-momentum losses at the start of the ramp. The simulation results are benchmarked against experimental data, demonstrating the accuracy of the newly developed tools used for the simulations.  
slides icon Slides WEC3C3 [1.641 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC3C3  
About • Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 19 October 2023
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THBP13 Recent Developments with the New Tools for Collimation Simulations in Xsuite simulation, coupling, scattering, proton 474
 
  • F.F. Van der Veken, A. Abramov, G. Broggi, F. Cerutti, M. D’Andrea, D. Demetriadou, L.S. Esposito, G. Hugo, G. Iadarola, B. Lindström, S. Redaelli, V. Rodin, N. Triantafyllou
    CERN, Meyrin, Switzerland
 
  Simulations of single-particle tracking involving collimation systems need dedicated tools to perform the different tasks needed. These include the accurate description of particle-matter interactions when a tracked particle impacts a collimator jaw; a detailed aperture model to identify the longitudinal location of losses; and others. One such tool is the K2 code in SixTrack, which describes the scattering of high-energy protons in matter. This code has recently been ported into the Xsuite tracking code that is being developed at CERN. Another approach is to couple the tracking with existing tools, such as FLUKA or Geant4, that offer better descriptions of particle-matter interactions and can treat lepton and ion beams. This includes the generation of secondary particles and fragmentation when tracking ions. In addition to the development of coupling with Geant4, the SixTrack-FLUKA coupling has recently been translated and integrated into the Xsuite environment as well. In this paper, we present the ongoing development of these tools. A thorough testing of the new implementation was performed, using as case studies various collimation layout configurations for the LHC Run 3.  
poster icon Poster THBP13 [2.785 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP13  
About • Received ※ 29 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 13 October 2023 — Issued ※ 23 October 2023
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THBP18 Revised Collimation Configuration for the Updated FCC-hh Layout optics, insertion, collider, hadron 495
 
  • A. Abramov, R. Bruce, M. Giovannozzi, G. Pérez Segurana, S. Redaelli, T. Risselada
    CERN, Meyrin, Switzerland
 
  The collimation system for the hadron Future Circular Collider (FCC-hh) must handle proton beams with an unprecedented nominal beam energy and stored beam energy in excess of 8 GJ, and protect the superconducting magnets and other sensitive equipment while ensuring a high operational efficiency. The recent development of the 16-dipole lattice baseline for the FCC-hh, and the associated layout changes, has necessitated an adaptation of the collimation system. A revised configuration of the collimation system is presented, considering novel high-beta optics in the betatron collimation insertion. Performance is evaluated through loss map studies, with a focus on losses in critical areas, including collimation insertions and experimental interaction regions.  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP18  
About • Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 19 October 2023
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THBP28 A Phase Trombone for the Fermilab PIP-II Beam Transfer Line booster, lattice, linac, injection 527
 
  • M. Xiao, D.E. Johnson, J.-F. Ostiguy
    Fermilab, Batavia, Illinois, USA
 
  The PIP-II beam transfer line (BTL) transports the beam from the PIP-II Linac to the Booster synchrotron ring. A crucial aspect of the BTL design is the collimation system which play a vital role in removing large ampli-tude particles that may otherwise miss the horizontal and vertical edges of the foil at the point of injection into the Booster. To ensure the effectiveness of the collimators, simulations were conducted to determine optimal place-ment within the BTL. These simulations revealed that precise control of the accumulated phase advances be-tween the collimators and the foil is critical. To achieve fine-tuning of the phase advance, a phase trombone was incorporated within the BTL. This paper presents the design and implementation details of this phase trom-bone  
poster icon Poster THBP28 [0.798 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP28  
About • Received ※ 20 September 2023 — Revised ※ 05 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 30 October 2023
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THBP49 Collimation of 400 MJ Beams at the LHC: The First Step Towards the HL-LHC Era proton, luminosity, operation, impedance 603
 
  • S. Redaelli, A. Abramov, D.B. Baillard, R. Bruce, R. Cai, F. Carra, M. D’Andrea, M. Di Castro, L. Giacomel, P.D. Hermes, B. Lindström, D. Mirarchi, N. Mounet, F.-X. Nuiry, A. Perillo Marcone, F.F. Van der Veken
    CERN, Meyrin, Switzerland
  • R. Cai
    EPFL, Lausanne, Switzerland
  • A. Vella
    University of Malta, Information and Communication Technology, Msida, Malta
 
  Funding: Work supported by the HL-LHC project.
An important upgrade programme is planned for the collimation system of the CERN Large Hadron Collider (LHC) in order to meet the challenges of the upcoming High-Luminosity LHC (HL-LHC) project. A first stage of the HL-LHC upgrade was already deployed during the last LHC Long Shutdown, offering important improvements of the collimation cleaning, a significant reduction of the impedance contribution and better cleaning of collisional debris, in particular for ion-ion collisions. This upgrade provides a critical opportunity to explore the LHC intensity limits during the LHC Run 3 and can provide crucial feedback to refine upgrade plans and operational scenarios in the HL-LHC era. This paper describes the performance of the upgraded LHC collimation system that has already enabled stored-beam energies larger than 400 MJ at the unprecedented beam energy of 6.8 TeV, and reviews further upgrade plans envisaged to reach 700 MJ beams at the HL-LHC.
 
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP49  
About • Received ※ 03 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 10 October 2023
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THBP53 Commissioning and Operation of the Collimation System at the RCS of CSNS controls, emittance, proton, MMI 615
 
  • S.Y. Xu, J. Chen, S. Wang
    IHEP, Beijing, People’s Republic of China
  • K. Zhou
    IHEP CSNS, Guangdong Province, People’s Republic of China
 
  For high-intensity proton synchrotrons, minimizing particle losses during machine operation is essential to avoid radiation damage. Uncontrolled beam loss posed a significant challenge to achieving higher beam intensity and power for high-intensity proton synchrotrons. The beam collimation system can remove halo particles and to localize the beam loss. The use of collimation system is an important means of controlling uncontrolled beam loss in high-power proton accelerators. To reduce the uncontrolled beam loss, a transverse collimation system was designed for the RCS of CSNS. The design transverse collimator is a two-stage collimator. During the beam commissioning of CSNS, the designed two-stage collimator has been changed to one-stage collimator to overcome the problem of low collimation efficiency caused by insufficient phase shift between the primary and secondary collimators. By optimizing the collimation system, the beam loss is well localized in the collimator area, effectively reducing uncontrolled beam loss. The beam power of CSNS achieved the design value of 100 kW with small uncontrolled beam loss.  
poster icon Poster THBP53 [0.780 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP53  
About • Received ※ 30 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 10 October 2023
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