A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z    

Métral, E.

Paper Title Page
MOPC001 Final Results from the Novel Multiturn Extraction Studies at CERN Proton Synchrotron 117
 
  • M. Giovannozzi, R. Cappi, S.S. Gilardoni, M. Martini, E. Métral, R.R. Steerenberg
    CERN, Geneva
  • A.-S. Müller
    FZK, Karlsruhe
  
  Recently a novel approach to perform multi-turn extraction was proposed based on beam splitting in the transverse phase space by means of trapping inside stable islands. An experimental campaign was launched since the year 2002 to assess the feasibility of such an extraction scheme at the CERN Proton Synchrotron. During the year 2004 run, a high-intensity single-bunch beam was successfully split and the generated beamlets separated without any measurable losses. The latest experimental results are presented and discussed in details in this paper. These achievements represent a substantial step forward with respect to what achieved in previous years, as only a low-intensity bunch could be split without losses. Furthermore, this opens the possibility of using such a technique for routine operation with the high-intensity proton beams required for the planned CERN Neutrino to Gran Sasso Project.  
MOPC003 Benchmarking of Simulation Codes Based on the Montague Resonance in the CERN Proton Synchrotron 330
 
  • I. Hofmann, G. Franchetti
    GSI, Darmstadt
  • J.F. Amundson, P. Spentzouris
    Fermilab, Batavia, Illinois
  • S.M. Cousineau, J.A. Holmes
    ORNL, Oak Ridge, Tennessee
  • M. Giovannozzi, E. Métral
    CERN, Geneva
  • F.W. Jones
    TRIUMF, Vancouver
  • A.U. Luccio
    BNL, Upton, Long Island, New York
  • S. Machida
    KEK, Ibaraki
  • J. Qiang, R.D. Ryne
    LBNL, Berkeley, California
  
  Experimental data on emittance exchange by the space charge driven ‘‘Montague resonance'' have been obtained at the CERN Proton Synchrotron in 2002-04 as a function of the working point. These data are used to advance the benchmarking of major simulation codes (ACCSIM, IMPACT, MICROMAP, ORBIT, SIMBAD, SIMPSONS, SYNERGIA) currently employed world-wide in the design or performance improvement of high intensity circular accelerators. In this paper we summarize the experimental findings and compare them with the first three steps of simulation results of the still progressing work.  
TOAC001 Overview of Impedance and Single-Beam Instability Mechanisms 14
 
  • E. Métral
    CERN, Geneva
  
  Single-bunch and coupled-bunch instability mechanisms will be reviewed in both longitudinal and transverse planes. The resistive-wall impedance will be discussed in the particular case of the LHC collimators, which reveal a new physical regime. Stabilization by Landau damping, feedbacks, or linear coupling between the transverse planes will also be treated. Benchmarking of analytical predictions with some instability codes will be shown as well as several experimental results.  
TPAP008 Measurements of the LHC Collimator Impedance with Beam in the SPS 1132
 
  • H. Burkhardt, G. Arduini, R.W. Assmann, F. Caspers, M. Gasior, A. Grudiev, O.R. Jones, T. Kroyer, E. Métral, S. Redaelli, G. Robert-Demolaize, F. Roncarolo, D. Schulte, R.J. Steinhagen, J. Wenninger, F. Zimmermann
    CERN, Geneva
  
  The transverse impedance of the LHC collimators will likely dominate the overall transverse impedance in the LHC at high energies and potentially limit the maximum intensity. A prototype collimator was recently tested in the SPS. Small, but significant tune shifts depending on the collimator position have been observed using different independent high resolution tune measurement methods. In addition trapped modes predicted from numerical simulation at the ends of the collimator jaws have been identified by bench measurement techniques as well as with the beam. We present a description of the measurements and an analysis of the results.  
TPAP007 LHC Collimation: Design and Results from Prototyping and Beam Tests 1078
 
  • R.W. Assmann, O. Aberle, G. Arduini, A. Bertarelli, H.-H. Braun, M. Brugger, H. Burkhardt, S. Calatroni, F. Caspers, E. Chiaveri, A. Dallocchio, B. Dehning, A. Ferrari, M. Gasior, A. Grudiev, E.B. Holzer, J.-B. Jeanneret, J.M. Jimenez, Y. Kadi, R. Losito, M. Magistris, A.M. Masi, M. Mayer, E. Métral, R. Perret, C. Rathjen, S. Redaelli, G. Robert-Demolaize, S. Roesler, M. Santana-Leitner, D. Schulte, P. Sievers, E. Tsoulou, H. Vincke, V. Vlachoudis, J. Wenninger
    CERN, Geneva
  • I. Baishev, I.L. Kurochkin
    IHEP Protvino, Protvino, Moscow Region
  • G. Spiezia
    Naples University Federico II, Science and Technology Pole, Napoli
  
  The problem of collimation and beam cleaning concerns one of the most challenging aspects of the LHC project. A collimation system must be designed, built, installed and commissioned with parameters that extend the present state-of-the-art by 2-3 orders of magnitude. Problems include robustness, cleaning efficiency, impedance and operational aspects. A strong design effort has been performed at CERN over the last two years. The system design has now been finalized for the two cleaning insertions. The adopted phased approach is described and the expected collimation performance is discussed. In parallel robust and precisely controllable collimators have been designed. Several LHC prototype collimators have been built and tested with the highest beam intensities that are presently available at CERN. The successful beam tests are presented, including beam-based setup procedures, a 2 MJ robustness test and measurements of the collimator-induced impedance. Finally, an outlook is presented on the challenges that are ahead in the coming years.  
ROPC004 Recent Intensity Increase in the CERN Accelerator Chain 413
 
  • E.N. Shaposhnikova, G. Arduini, T. Bohl, M. Chanel, R. Garoby, S. Hancock, K. Hanke, T.P.R. Linnecar, E. Métral, R.R. Steerenberg, B. Vandorpe
    CERN, Geneva
  
  Future requests for protons from the physics community at CERN, especially after the start-up of the CNGS experiments in 2006, can only be satisfied by a substantial increase in the SPS beam intensity per pulse. In September 2004 a three weeks beam run was dedicated to high intensity; all accelerators in the chain were pushed to their limits to study intensity restrictions and find possible solutions. New record intensities were obtained in the accelerators of the PS & SPS Complex with this fixed-target type beam which is different from the nominal LHC beam. The challenges in producing this high-intensity beam are described together with the measures needed to make it fully operational.