Author: Meddahi, M.
Paper Title Page
TUXA02 Upgrade Plans for the LHC Injector Complex 1010
  • R. Garoby, H. Damerau, S.S. Gilardoni, B. Goddard, K. Hanke, A.M. Lombardi, M. Meddahi, B. Mikulec, E.N. Shaposhnikova, M. Vretenar
    CERN, Geneva, Switzerland
  Challenging beams with much higher brightness than today are required for the LHC to achieve its high luminosity objective after the year 2020. It is the purpose of the LHC Injectors Upgrade (LIU) Project to achieve this result, consolidating and upgrading the existing set of ageing synchrotrons (PSB, PS and SPS), and using the new linac presently in construction (Linac4). The anticipated beam characteristics are described and compared to the known limitations in the different accelerators. The foreseen solutions are outlined as well as the planning for their implementation.  
slides icon Slides TUXA02 [72.367 MB]  
TUPPR093 Sources and Solutions for LHC Transfer Line Stability Issues 2047
  • L.N. Drosdal, W. Bartmann, C. Bracco, B. Goddard, V. Kain, G. Le Godec, M. Meddahi, J.A. Uythoven
    CERN, Geneva, Switzerland
  The LHC is filled through two 3km transfer lines from the last pre-injector, the SPS. Safe injection into the LHC requires stable trajectories in the transfer lines. During the LHC proton operations 2011 instabilities were observed. In particular shot-by-shot and bunch-by-bunch variations cause difficulties for steering of the beam and can potentially cause high beam losses at injection. The causes of these instabilities have been studied and will be presented in this paper. Based on the studies solutions will be proposed and finally the effects of the solutions will be studied.  
TUPPR094 SPS Transverse Beam Scraping and LHC Injection Losses 2050
  • L.N. Drosdal, W. Bartmann, C. Bracco, K. Cornelis, B. Goddard, V. Kain, M. Meddahi, E. Veyrunes
    CERN, Geneva, Switzerland
  Machine protection sets strict requirements for the quality of the injected beam, in particular in the transverse plane. Losses at aperture restrictions and protection elements have to be kept at a minimum. Particles in the beam tails are lost at the tight transfer line collimators and can trigger the LHC beam abort system. These particles have to be removed by scrapers in the vertical and horizontal plane in the SPS. Scraping has become vital for high intensity LHC operation. This paper shows the dependence of injection quality on the SPS scraping and discusses an improved scraper setting up strategy for better reproducibility with the current scraper system.  
MOPPD058 LHC Abort Gap Cleaning Studies during Luminosity Operation 496
  • E. Gianfelice-Wendt
    Fermilab, Batavia, USA
  • W. Bartmann, A. Boccardi, C. Bracco, E. Bravin, B. Goddard, W. Höfle, D. Jacquet, A. Jeff, V. Kain, M. Meddahi, F. Roncarolo, J.A. Uythoven, D. Valuch
    CERN, Geneva, Switzerland
  The presence of significant intensities of un-bunched beam is a potentially serious issue in the LHC. Procedures using damper kickers for cleaning both Abort Gap (AG) and buckets targeted for injection, are currently in operation at flat bottom. Recent observations of relatively high population of the AG during physics runs brought up the need for AG cleaning during luminosity operation as well. In this paper the results of experimental studies performed in October 2011 are presented.