Author: Bulyak, E.V.
Paper Title Page
MOPPP004 Further Study on Fast Cooling in Compton Storage Rings 571
 
  • E.V. Bulyak
    NSC/KIPT, Kharkov, Ukraine
  • J. Urakawa
    KEK, Ibaraki, Japan
  • F. Zimmermann
    CERN, Geneva, Switzerland
 
  Compton sources can produce gamma-ray photons of ultimate intensity, but suffer from the large recoils experienced by the circulating electrons scattering off the laser photons. We have previously proposed a scheme called asymmetric fast cooling to reduce the beam energy spread in Compton rings. This report presents results of further studies on the fast cooling. In particular, we show that (1) a proper asymmetric setup of the scattering point results in significant reduction of the quantum losses of electrons in Compton rings with moderate energy acceptance, and (2) the optimized pulsed mode of operation in synchrotron-dominated rings enhances the overall performance of such gamma-ray sources. Theoretical results presented are in good accordance with numerical simulations. We discuss the performance of an existing storage ring such as KEK ATF DR equipped with an optical cavity and presently available laser system.  
 
WEPPR076 Positron Options for the Linac-ring LHeC 3108
 
  • F. Zimmermann, O.S. Brüning, Y. Papaphilippou, D. Schulte, P. Sievers
    CERN, Geneva, Switzerland
  • H.-H. Braun
    Paul Scherrer Institut, Villigen, Switzerland
  • E.V. Bulyak
    NSC/KIPT, Kharkov, Ukraine
  • M. Klein
    The University of Liverpool, Liverpool, United Kingdom
  • L. Rinolfi
    JUAS, Archamps, France
  • A. Variola, Z.F. Zomer
    LAL, Orsay, France
  • V. Yakimenko
    BNL, Upton, Long Island, New York, USA
 
  The full physics program of a future Large Hadron electron Collider (LHeC) requires both pe+ and pe- collisions. For a pulsed 140-GeV or an ERL-based 60-GeV Linac-Ring LHeC this implies a challenging rate of, respectively, about 1.8·1015 or 4.4·1016 e+/s at the collision point, which is about 300 or 7000 times the past SLC rate. We consider providing this e+ rate through a combination of measures: (1) Reducing the required production rate from the e+ target through colliding e+ (and the LHC protons) several times before deceleration, by reusing the e+ over several acceleration/deceleration cycles, and by cooling them, e.g., with a compact tri-ring scheme or a conventional damping ring in the SPS tunnel. (2) Using an advanced target, e.g., W-granules, rotating wheel, sliced-rod converter, or liquid metal jet, for converting gamma rays to e+. (3) Selecting the most powerful of several proposed gamma sources, namely Compton ERL, Compton storage ring, coherent pair production in a strong laser, or high-field undulator radiation from the high-energy lepton beam. We describe the various concepts, present example parameters, estimate the electrical power required, and mention open questions.