Author: Sapinski, M.
Paper Title Page
MOPPC004 Experiments on the Margin of Beam Induced Quenches for LHC Superconducting Quadrupole Magnet in the LHC 124
  • C. Bracco, W. Bartmann, M. Bednarek, B. Goddard, E.B. Holzer, A. Nordt, M. Sapinski, R. Schmidt, M. Solfaroli Camillocci, M. Zerlauth, E.N. del Busto
    CERN, Geneva, Switzerland
  Protection of LHC equipment relies on a complex system of collimators to capture injected or circulating beam in case of LHC injection kicker magnet failures. However, for specific failures of the injection kicker, the beam can graze the injection protection collimators and induce quenches of downstream superconducting magnets. This occurred twice during 2011 operation and can also not be excluded during further operation. Tests were performed during Machine Development periods of the LHC to assess the quench margin of the quadrupole located just downstream of the last injection protection collimator in point 8. In addition to the existing Quench Protection System, a special monitoring instrumentation was installed at this magnet to detect any resistance increase below the quench limit. The correlation between the magnet and Beam Loss Monitor signals was analysed for different beam intensities and magnet current. The results of the experiments are presented in this paper.  
TUOAB02 Investigation of the Use of Silicon, Diamond and Liquid Helium Detectors for Beam Loss Measurements at 2 Kelvin 1080
  • C. Kurfuerst, B. Dehning, W.T. Eisel, M. Sapinski
    CERN, Geneva, Switzerland
  • V. Eremin
    IOFFE, St. Petersburg, Russia
  • C. Fabjan
    HEPHY, Wien, Austria
  At the triplet magnets, close to the interaction regions of the LHC, the current Beam Loss Monitoring (BLM) system is very sensitive to the debris from the collisions. For future beams with higher energy and higher luminosity this will lead to a situation in which the BLM system can no longer distinguish between these interaction products and quench-provoking beam losses from the primary proton beams. The solution investigated is to locate the detectors as close as possible to the superconducting coil, i.e. the element to be protected. This means putting detectors inside the cold mass of the superconducting magnets at 1.9 K. As possible candidates for such loss monitors, diamond, silicon and a liquid helium chamber have been tested in a proton beam at liquid helium temperatures. The initial promising results from these tests will be presented and discussed in this contribution.  
slides icon Slides TUOAB02 [3.412 MB]  
THPPR037 Estimation of Thresholds for the Signals of the BLMs around the LHC Final Focus Triplet Magnets 4053
  • M. Sapinski, F. Cerutti, B. Dehning, A. Ferrari, A. Lechner, M. Mauri, A. Mereghetti
    CERN, Geneva, Switzerland
  • C. Hoa
    CEA-CENG, Grenoble, France
  The Interaction Points of the Large Hadron Collider are the regions where the two circulating beams collide. Hence, the magnets the closest to any Interaction Point are exposed to an elevated radiation field due to the collision debris. In this study the signal in the Beam Loss Monitors due to the debris is estimated and compared with the measurements. In addition, the energy density in the coils and the signal in the Beam Loss Monitors at quench are estimated for various beam loss scenarios. It is shown that the Beam Loss Monitors, as presently installed on the outside of the vacuum vessel of the magnets, cannot disentangle the signals due to a localised halo loss from that of the constant signal due to the collision debris.