Author: Drosdal, L.N.
Paper Title Page
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.