Author: Scandale, W.
Paper Title Page
MOPWO035 Layouts for Crystal Collimation Tests at the LHC 966
 
  • D. Mirarchi, S. Redaelli, W. Scandale
    CERN, Geneva, Switzerland
  • D. Mirarchi
    The Imperial College of Science, Technology and Medicine, London, United Kingdom
  • V. Previtali
    Fermilab, Batavia, USA
 
  Various studies have been carried out in the past years regarding crystal collimation for the LHC. A new extensive campaign of simulations was performed to determine optimum layouts for beam tests at the LHC. The layouts are determined based on semi-analytical models for the dynamics of channeled particles. Detailed SixTrack tracking with all collimators of the ring are then used to validate the different options. An overview of the ongoing studies is given. Comparative studies between the present collimation system, the crystal collimation system, and different crystal collimation layout are presented.  
 
THPFI059 Robustness Test of a Silicon Strip Crystal for Crystal-assisted Collimation Studies in the LHC 3427
 
  • A. Lechner, J. Blanco Sancho, F. Burkart, M. Calviani, M. Di Castro, Y. Gavrikov, J. Lendaro, F. Loprete, R. Losito, C. Maglioni, A. Masi, S. Montesano, A. Perillo-Marcone, P.S. Roguet, W. Scandale, D. Wollmann
    CERN, Geneva, Switzerland
  • J. Blanco Sancho
    EPFL, Lausanne, Switzerland
  • F. Burkart
    IAP, Frankfurt am Main, Germany
  • Y. Gavrikov
    PNPI, Gatchina, Leningrad District, Russia
  • V. Guidi, A. Mazzolari
    INFN-Ferrara, Ferrara, Italy
  • V. Guidi, A. Mazzolari
    UNIFE, Ferrara, Italy
  • W. Scandale
    LAL, Orsay, France
 
  Over the past years, the UA9 experiment has successfully demonstrated the viability of enhancing the collimation efficiency of proton and ion beams in the SPS by means of bent crystals. An extension of UA9 to the LHC has been recently approved. The conditions imposed by the LHC operational environment, in particular the tremendous energy density of the beam, require a reliable understanding of the crystal integrity in view of potential accident scenarios such as an asynchronous beam dump. For this purpose, irradiation tests have been performed at the CERN-HiRadMat facility to examine the mechanical strength of a silicon strip crystal in case of direct beam impact. The tests were carried out using a 440 GeV proton beam of 0.5 mm transverse size. The crystal, 3 mm long in beam direction, was exposed to a total of 2*1014 protons, with individual pulse intensities reaching up to 3*1013. First visual inspections reveal no macroscopic damage to the crystal. Complementary post-irradiation tests are foreseen to assess microscopic lattice damage as well as the degradation of the channelling efficiency.
On behalf of the UA9 Collaboration.
 
 
THPFI064 Crystal-assisted Collimation Experiment from the SPS to the LHC 3442
 
  • W. Scandale, D. Mirarchi, S. Redaelli
    CERN, Geneva, Switzerland
 
  UA9 was operated in the CERN-SPS for more than six years in view of investigating the feasibility of the halo collimation assisted by bent crystals. Two-millimeter-long silicon crystals, with bending angles of about 150 μrad, are used as primary collimators. The crystal collimation process is obtained consistently through channeling with high efficiency, showing a steady reduction of almost one order of magnitude of the loss rate at the onset of the channeling process. This result holds both for protons and for lead-ions. The corresponding loss map in the accelerator ring is accordingly reduced. These observations strongly support our expectation that the coherent deflection of the beam halo by a bent crystal should enhance the collimation efficiency also in LHC. After a concise description of the results collected in the SPS we propose a scenario to integrate bent crystals in the LHC collimation system for machine experiment.  
 
THPFI059 Robustness Test of a Silicon Strip Crystal for Crystal-assisted Collimation Studies in the LHC 3427
 
  • A. Lechner, J. Blanco Sancho, F. Burkart, M. Calviani, M. Di Castro, Y. Gavrikov, J. Lendaro, F. Loprete, R. Losito, C. Maglioni, A. Masi, S. Montesano, A. Perillo-Marcone, P.S. Roguet, W. Scandale, D. Wollmann
    CERN, Geneva, Switzerland
  • J. Blanco Sancho
    EPFL, Lausanne, Switzerland
  • F. Burkart
    IAP, Frankfurt am Main, Germany
  • Y. Gavrikov
    PNPI, Gatchina, Leningrad District, Russia
  • V. Guidi, A. Mazzolari
    INFN-Ferrara, Ferrara, Italy
  • V. Guidi, A. Mazzolari
    UNIFE, Ferrara, Italy
  • W. Scandale
    LAL, Orsay, France
 
  Over the past years, the UA9 experiment has successfully demonstrated the viability of enhancing the collimation efficiency of proton and ion beams in the SPS by means of bent crystals. An extension of UA9 to the LHC has been recently approved. The conditions imposed by the LHC operational environment, in particular the tremendous energy density of the beam, require a reliable understanding of the crystal integrity in view of potential accident scenarios such as an asynchronous beam dump. For this purpose, irradiation tests have been performed at the CERN-HiRadMat facility to examine the mechanical strength of a silicon strip crystal in case of direct beam impact. The tests were carried out using a 440 GeV proton beam of 0.5 mm transverse size. The crystal, 3 mm long in beam direction, was exposed to a total of 2*1014 protons, with individual pulse intensities reaching up to 3*1013. First visual inspections reveal no macroscopic damage to the crystal. Complementary post-irradiation tests are foreseen to assess microscopic lattice damage as well as the degradation of the channelling efficiency.
On behalf of the UA9 Collaboration.