Author: Perillo Marcone, A.
Paper Title Page
MOPOR008 Beam Induced RF Heating in LHC in 2015 602
  • B. Salvant, O. Aberle, M. Albert, R. Alemany-Fernandez, G. Arduini, J. Baechler, M.J. Barnes, P. Baudrenghien, O.E. Berrig, N. Biancacci, G. Bregliozzi, J.V. Campelo, F. Carra, F. Caspers, P. Chiggiato, A. Danisi, H.A. Day, M. Deile, D. Druzhkin, J.F. Esteban Müller, S. Jakobsen, J. Kuczerowski, A. Lechner, R. Losito, A. Masi, N. Minafra, E. Métral, A.A. Nosych, A. Perillo Marcone, D. Perini, S. Redaelli, F. Roncarolo, G. Rumolo, E.N. Shaposhnikova, J.A. Uythoven, C. Vollinger, A.J. Välimaa, N. Wang, M. Wendt, J. Wenninger, C. Zannini
    CERN, Geneva, Switzerland
  • M. Bozzo
    INFN Genova, Genova, Italy
  • J.F. Esteban Müller
    EPFL, Lausanne, Switzerland
  • N. Wang
    IHEP, Beijing, People's Republic of China
  Following the recurrent beam induced RF issues that perturbed LHC operation during LHC Run 1, a series of actions were put in place to minimize the risk that similar issues would occur in LHC Run 2: longitudinal impedance reduction campaign and/or improvement of cooling for equipment that were problematic or at the limit during Run 1, stringent constraints enforced on new equipment that would be installed in the machine, tests to control the bunch length and longitudinal distribution, additional monitoring of temperature, new monitoring tools and warning chains. This contribution reports the outcome of these actions, both successes as well as shortcomings, and details the lessons learnt for the future runs.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR008  
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MOPOR010 Impedance Measurements and Simulations on the TCTP and TDI LHC Collimators 610
  • N. Biancacci, F. Caspers, A. Grudiev, J. Kuczerowski, I. Lamas Garcia, A. Lechner, E. Métral, A. Passarelli, A. Perillo Marcone, B. Salvant, J.A. Uythoven
    CERN, Geneva, Switzerland
  • O. Frasciello, M. Zobov
    INFN/LNF, Frascati (Roma), Italy
  • A. Mostacci
    Rome University La Sapienza, Roma, Italy
  • N. Mounet
    EPFL, Lausanne, Switzerland
  The LHC collimation system is a critical element for the safe operation of the LHC machine and is subject to continuous performance monitoring, hardware upgrade and optimization. In this work we will address the impact on impedance of the upgrades performed on the TDI injection protection collimator, where the absorber material has been changed to mitigate the device heating observed in machine operation, and on selected secondary (TCS) and tertiary (TCT) collimators, where beam position monitors (BPM) have been embedded for faster jaw alignment. Concerning the TDI, we will present the RF measurements performed before and after the upgrade, comparing the result to heating and tune shift beam measurements. For the TCTs, we will study how the higher order modes (HOM) introduced by the BPM addition have been cured by means of ferrite placement in the device. The impedance mitigation campaign has been supported by RF measurements whose results are in good agreement with GdfidL and CST simulations. The presence of undamped low frequency modes is proved not to be detrimental to the safe LHC operation.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR010  
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TUPMR050 Upgrades to the SPS-to-LHC Transfer Line Beam Stoppers for the LHC High-Luminosity Era 1367
  • V. Kain, R. Esposito, M.A. Fraser, B. Goddard, M. Meddahi, A. Perillo Marcone, G.E. Steele, F.M. Velotti
    CERN, Geneva, Switzerland
  Each of the 3 km long transfer lines between the SPS and the LHC is equipped with two beam stoppers (TEDs), one at the beginning of the line and one close to the LHC injection point, which need to absorb the full transferred beam. The beam stoppers are used for setting up the SPS extractions and transfer lines with beam without having to inject into the LHC. Energy deposition and thermo-mechanical simulations have, however, shown that the TEDs will not be robust enough to safely absorb the high intensity beams foreseen for the high-luminosity LHC era. This paper will summarize the simulation results and limitations for upgrading the beam stoppers. An outline of the hardware upgrade strategy for the TEDs together with modifications to the SPS extraction interlock system to enforce intensity limitations for beam on the beam stoppers will be given.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR050  
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