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Robert-Demolaize, G.

Paper Title Page
TUPAS095 Experiments with a DC Wire in RHIC 1859
  • W. Fischer, N. P. Abreu, R. Calaga, G. Robert-Demolaize
    BNL, Upton, Long Island, New York
  • U. Dorda, J.-P. Koutchouk, F. Zimmermann
    CERN, Geneva
  • A. C. Kabel
    SLAC, Menlo Park, California
  • H. J. Kim, T. Sen
    Fermilab, Batavia, Illinois
  • J. Qiang
    LBNL, Berkeley, California
  Funding: Work supported by U. S. DOE under contract No DE-AC02-98CH1-886.

A DC wire has been installed in RHIC to explore the long-range beam-beam effect, and test its compensation. We report on experiments that measure the effect of the wire's electro-magnetic field on the beam's lifetime and tune distribution, and accompanying simulations.

TUPAN087 Scenarios for Beam Commissioning of the LHC Collimation System 1577
  • C. Bracco, R. W. Assmann, C. Bracco, S. Redaelli, G. Robert-Demolaize
    CERN, Geneva
  A complex system of collimators has been designed to protect the superconducting LHC magnets against quench and damage from the high intensity proton beams. The considerable number of collimators and the resulting number of degrees of freedom for their set-up requires a well prepared commissioning strategy. Efficiency studies for various implementations of the LHC collimation system have been performed, taking into account the evolution in optics and beam intensity according to the LHC commissioning schedule. This paper explains the present plans for the set-up sequence of collimators and discusses the relevant tolerances induced from the collimation system for the first years of the LHC operation.  
TUPAN100 Performance Reach of the 1613
  • G. Robert-Demolaize, R. W. Assmann, C. Bracco, S. Redaelli, Th. Weiler
    CERN, Geneva
  State-of-the-art tracking tools have been developed for detailed LHC collimation and beam loss studies. This includes full chromatic treatment of both beam lines and error models. This paper reviews the main results on the performance reach of the multi-stage LHC collimation system that is being installed in the LHC. Limitations on the allowed proton loss rates and the stored intensity can be derived from the comparison of local losses with estimated quench limits for the superconducting magnets. The origins of the cleaning-related performance limitations are presented and possible improvements are discussed.  
TUPAN107 Beam Loss Response Measurements with an LHC Prototype Collimator in the SPS 1622
  • Th. Weiler, G. Arduini, R. W. Assmann, C. Bracco, H.-H. Braun, B. Dehning, P. Gander, E. B. Holzer, M. Jonker, R. Losito, A. Masi, L. Ponce, S. Redaelli, G. Robert-Demolaize, M. Sobczak, J. Wenninger
    CERN, Geneva
  Beam tests with an LHC prototype collimator were performed at the SPS in autumn 2006. Applying a new collimator control system many new beam measurements were performed. This contribution presents results on collimator-induced beam loss measurements and their applications to beam-based alignment of collimators and measurements of the beam size and position. Interesting features of the recorded beam loss signals are illustrated and possible impacts for LHC operation are discussed. The measured loss distributions around the full SPS ring are analyzed and compared with simulations.  
WEOAC03 Transverse Impedance of LHC Collimators 2003
  • E. Metral, G. Arduini, R. W. Assmann, A. Boccardi, T. Bohl, C. Bracco, F. Caspers, M. Gasior, O. R. Jones, K. K. Kasinski, T. Kroyer, S. Redaelli, G. Robert-Demolaize, G. Rumolo, R. J. Steinhagen, Th. Weiler, F. Zimmermann
    CERN, Geneva
  • F. Roncarolo
    UMAN, Manchester
  • B. Salvant
    EPFL, Lausanne
  The transverse impedance in the LHC is expected to be dominated by the numerous collimators, most of which are made of Fibre-Reinforced-Carbon to withstand the impacts of high intensity proton beams in case of failures, and which will be moved very close to the beam, with full gaps of few millimetres, in order to protect surrounding super-conducting equipments. We present an estimate of the transverse resistive-wall impedance of the LHC collimators, the total impedance in the LHC at injection and top energy, the induced coupled-bunch growth rates and tune shifts, and finally the result of the comparison of the theoretical predictions with measurements performed in 2004 and 2006 on a prototype collimator installed in the SPS.  
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THPAN065 Beam Loss Map Simulations and Measurements in the CERN PS 3372
  • J. Barranco, O. E. Berrig, S. S. Gilardoni, J. B. Jeanneret, Y. Papaphilippou
    CERN, Geneva
  • G. Robert-Demolaize
    BNL, Upton, Long Island, New York
  Numerical tools providing detailed beam loss maps, recently developed for the design of the LHC collimation system, were adapted to the CERN Proton Synchrotron in order to reproduce the observed beam loss patterns. Using a MADX optics sequence model, these tools are able to track a large number of particles with Sixtrack and interact with a realistic aperture model to simulate particle losses all around the ring. The modeled loss maps were finally compared with beam loss measurements at several energies and for a variety of beams accelerated in the synchrotron.