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Jones, F. W.

Paper Title Page
THPAN006 Simulation of Decays and Secondary Ion Losses in a Betabeam Decay Ring 3232
 
  • F. W. Jones
    TRIUMF, Vancouver
  • E. Y. Wildner
    CERN, Geneva
 
  The beta decay of circulating ions in the decay ring of a Betabeam facility will give rise to secondary ions which differ in charge from the primary ions and will follow widely off-momentum orbits. A small fraction of these ions will be lost in the long straights, but the great majority of them will be lost in the arcs. Profiling of the losses requires detailed knowledge of the paths of these ions, which are distributed in phase space as well as around the ring circumference. We describe here a comprehensive model of ion decay, secondary ion tracking, and loss detection, which has been implemented in the tracking and simulation code Accsim. Methods have been developed to accurately track ions at large momentum deviations not amenable to conventional multiparticle tracking codes, as well as to detect their impact coordinates on vacuum chamber walls (possibly inside magnetic elements). In our simulation we have also included absorbers which are needed, along with appropriate lattice optimisations, to localize the majority of losses outside of the dipoles. From simulation results, some estimates of decay ring performance (in terms of loss concentration and management) will be given.  
THPAN007 Parallel Beam-Beam Simulation Incorporating Multiple Bunches and Multiple Interaction Regions 3235
 
  • F. W. Jones
    TRIUMF, Vancouver
  • W. Herr
    CERN, Geneva
  • T. Pieloni
    EPFL, Lausanne
 
  The simulation code COMBI has been developed to enable the study of beam-beam effects in the full collision scenario of the LHC, with multiple bunches interacting at multiple head-on and long-range collision points. The code is structured in a general way, allowing any number of bunches and interaction points (IP's) and procedural options for collisions, beam transport, and output of statistics and coherent mode data. The scale of this problem escalates into the parallel computing arena, and herein we will describe the construction of an MPI-based version of COMBI able to utilize arbitrary numbers of processors to support efficient calculation of multi-bunch multi-IP interactions and transport. After an overview of the basic methods and numerical components of the code, the computational framework will be described in detail and the parallel efficiency and scalability of the code will be evaluated.