Author: Tuckmantel, J.     [Tückmantel, J.]
Paper Title Page
MOPPC003 Very Fast LHC Crab Cavity Failures and their Mitigation 121
  • T. Baer, R. Calaga, R. De Maria, S.D. Fartoukh, E. Jensen, R. Tomás, J. Tückmantel, J. Wenninger, B. Yee-Rendon, F. Zimmermann
    CERN, Geneva, Switzerland
  • T. Baer
    University of Hamburg, Hamburg, Germany
  For the high-luminosity LHC upgrade program (HL-LHC), the installation of crab cavities (CCs) is needed to compensate the geometric luminosity loss due to the crossing angle and for luminosity leveling [*]. The baseline is a local scheme with CCs around the ATLAS and CMS experiments. In a failure case (e.g. a control failure or arcing in the coupler), the voltage and/or phase of a CC can change significantly with a very fast time constant of the order of 1 to 10 LHC turns. This can lead to large, global betatron oscillations of the beam. The impact of CC failures on the beam dynamics is discussed and the results from dedicated simulations are presented. Mitigation strategies to limit the impact of CC failures to an acceptable level are proposed.
* F. Zimmermann and O. Brüning, “Parameter Space for the LHC High-Luminosity Upgrade”, IPAC'12, MOPPC005, May 2012.
WEPPC028 Slim Elliptical Cavity at 800 MHz for Local Crab Crossing 2263
  • L. Ficcadenti, J. Tückmantel
    CERN, Geneva, Switzerland
  A slim highly eccentric elliptical Crab cavity with vertical deflection at 800 MHz, compatible to beam line distances everywhere in the LHC ring, was designed. It is a good fall-back solution in case of problems with new compact 400 MHz designs. Simulated RF characteristics of the delfecting mode, HOM spectra and damping, tuning and multipacting effects are presented. First the most simple HOM coupling system was investigated. The rejection of the working mode was not sufficient and a notch filter was added. Results of both cases will be presented.  
THPPP007 Proton-Beam Emittance Growth in SPS Coasts 3737
  • R. Calaga, L. Ficcadenti, E. Métral, R. Tomás, J. Tückmantel, F. Zimmermann
    CERN, Geneva, Switzerland
  Funding: This work partially supported by the US Department of Energy through the US LHC Accelerator Research Program (LARP).
Proton-beam transverse emittance growth rates have been measured during SPS coasts to assess the possibility of using the SPS as a testbed for the LHC prototype crab cavities. The SPS measurements in coasts were performed at different beam energies, for varying RF voltage, beam intensity, and chromaticity. Results from these measurements are presented with potential explanations for the observed emittance growth.