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Dorda, U.

Paper Title Page
TUPAN091 LHC Beam-beam Compensation Using Wires and Electron Lenses 1589
  • U. Dorda, F. Zimmermann
    CERN, Geneva
  • W. Fischer
    BNL, Upton, Long Island, New York
  • V. D. Shiltsev
    Fermilab, Batavia, Illinois
  We present weak-strong simulation results for a possible application of current-carrying wires and electron lenses to compensate the LHC long-range and head-on beam-beam interaction, respectively, for nominal and Pacman bunches. We show that these measures have the potential to considerably increase the beam-beam limit, allowing for a corresponding increase in peak luminosity  
TUPAS089 Small Angle Crab Compensation for LHC IR Upgrade 1853
  • R. Calaga
    BNL, Upton, Long Island, New York
  • K. Akai, K. Ohmi, K. Oide
    KEK, Ibaraki
  • U. Dorda, R. Tomas, F. Zimmermann
    CERN, Geneva
  Funding: This work is partially supported by the U. S. DOE

A small angle (< 1mrad) crab scheme is an attractive option for the LHC luminosity upgrade to recover the geometric luminosity loss from the finite crossing angle, which steeply increases to unacceptable levels as the IP beta function is reduced below its nominal value. The crab compensation in the LHC can be accomplished using only two sets of deflecting rf cavities, placed in collision-free straight sections of LHC to nullify the crossing angles at IP1 & IP5. We present IR optics configurations with low-angle crab crossing, study the beam-beam performance and proton-beam emittance growth in the presence of crab compensation, lattice errors, crab RF noise sources. We also explore a 400MHz superconducting cavity design and discuss the pertinent RF challenges.

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.

THPAN074 Space-Charge Compensation Options for the LHC Injector Complex 3390
  • F. Zimmermann, M. Aiba, M. Chanel, U. Dorda, R. Garoby, J.-P. Koutchouk, M. Martini, E. Metral, Y. Papaphilippou, W. Scandale
    CERN, Geneva
  • G. Franchetti
    GSI, Darmstadt
  • V. D. Shiltsev
    Fermilab, Batavia, Illinois
  Space-charge effects have been identified as the most serious intensity limitation in the CERN PS and PS booster, on the way towards ultimate LHC performance and beyond. We here explore the application of several previously proposed space-compensation methods to the two LHC pre-injector rings, for each scheme discussing its potential benefit, ease of implementation, beam-dynamics risk, and the R&D programme required. The methods considered include tune shift and resonance compensation via octupoles, nonlinear chromaticity, or electron lenses, and beam neutralization by an electron cloud, plasma or negative ions.