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Garrel, N.

Paper Title Page
TUPAN086 An Improved Beam Screen for the LHC Injection Kickers 1574
  • M. J. Barnes, F. Caspers, L. Ducimetiere, N. Garrel, T. Kroyer
    CERN, Geneva
  The two LHC injection kicker magnet systems must produce a kick of 1.3 T.m with a flattop duration variable up to 7860 ns, and rise and fall times of less than 900 ns and 3000 ns, respectively. Each system is composed of two resonant charging power supplies and four 5 Ω transmission line kicker magnets with matched terminating resistors and pulse forming networks. A beam screen is placed in the aperture of the magnets: the screen consists of a ceramic tube with conductors on the inner wall. The conductors provide a path for the image current of the, high intensity, LHC beam and screen the ferrite against Wake fields. The conductors initially used gave adequately low beam impedance however inter-conductor discharges occurred during pulsing of the magnet: an alternative design was discharge free at the nominal operating voltage but the beam impedance was too high for the ultimate LHC beam. This paper presents the results of a new development undertaken to meet the often conflicting requirements for low beam impedance, shielding of the ferrite, fast field rise time and good electrical behaviour. High voltage test results and thermal measurements are also presented.