Author: Pivi, M.T.F.
Paper Title Page
WEPEA013 Electron Cloud Studies for the Upgrade of the CERN PS 2522
  • G. Iadarola
    Naples University Federico II, Science and Technology Pole, Napoli, Italy
  • H. Damerau, S.S. Gilardoni, G. Iadarola, S. Rioja Fuentelsaz, G. Rumolo, G. Sterbini, C. Yin Vallgren
    CERN, Geneva, Switzerland
  • M.T.F. Pivi
    SLAC, Menlo Park, California, USA
  The observation of a significant dynamic pressure rise as well as measurements with dedicated detectors indicate that an electron cloud develops in the CERN PS during the last stages of the RF manipulations for the production of LHC type beams, especially with 25ns bunch spacing. Although presently these beams are not degraded by the interaction with the electron cloud, which develops only during few milliseconds before extraction, the question if this effect could degrade the future high intensity and high brightness beams foreseen by the LHC Injectors Upgrade (LIU) project is still open. Therefore several studies are being carried out employing both simulations and measurements with the electron cloud detectors in the machine. The aim is to develop a reliable electron cloud model of the PS vacuum chambers in order to identify possible future limitations and find suitable countermeasures.  
WEPME042 Modelling and Studies for a Wideband Feedback System for Mitigation of Transverse Single Bunch Instabilities 3019
  • K.S.B. Li, W. Höfle, G. Rumolo
    CERN, Geneva, Switzerland
  • J.M. Cesaratto, J.E. Dusatko, J.D. Fox, M.T.F. Pivi, K.M. Pollock, C.H. Rivetta, O. Turgut
    SLAC, Menlo Park, California, USA
  As part of the LHC injector upgrade a wideband feedback system is under study for mitigation of coherent single bunch instabilities. This type of system may provide a generic way of shifting the instability threshold to regions that are currently inaccessible, thus, boosting the brightness of future beams. To study the effectiveness of such systems, a numerical model has been developed that constitutes a realistic feedback system including real transfer functions for pickup and kicker, realistic N-tap FIR and IIR filters as well as noise and saturation effects. Simulations of SPS cases have been performed with HeadTail to evaluate the feedback effectiveness in the presence of electron clouds and TMCI. Some results are presented addressing bandwidth limitations, noise issues and amplifier power requirements.