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Morvillo, M.

Paper Title Page
FRPMN070 Controlled Longitudinal Emittance Blow-up in the CERN PS 4186
  • H. Damerau, M. Morvillo, E. N. Shaposhnikova, J. Tuckmantel, J.-L. Vallet
    CERN, Geneva
  The longitudinal emittance of the bunches in the CERN PS must be increased before transition crossing to avoid beam loss due to a fast vertical instability. This controlled blow-up is essential for all high-intensity beams in the PS, including those for transfer to the LHC. The higher harmonic 200 MHz RF system (six cavities) used for this blow-up has to generate a total RF voltage which, for the most demanding blow-up, is comparable to the voltage of the main RF cavities. The system is presently subject to a major upgrade and a possible reduction in the number of higher harmonic RF cavities installed is under consideration. To determine the minimum required, detailed simulations and machine development studies to optimize the longitudinal blow-up have been performed. Further options to produce the required longitudinal emittance using other RF systems are also analyzed. The results obtained for the different scenarios for the longitudinal blow-up are presented and compared in this paper.  
FRPMN076 Nominal LHC Beam Instability Observations in the CERN Proton Synchrotron 4222
  • R. R. Steerenberg, G. Arduini, E. Benedetto, A. Blas, W. Hofle, E. Metral, M. Morvillo, C. Rossi, G. Rumolo
    CERN, Geneva
  The nominal LHC beam has been produced successfully in the CERN Proton Synchrotron since 2003. However, after having restarted the CERN PS in spring 2006, the LHC beam was set-up and observed to be unstable on the 26 GeV/c extraction flat top. An intensive measurement campaign was made to understand the instability and to trace its source. This paper presents the observations, possible explanations and the necessary measures to be taken in order to avoid this instability in the future.