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Peggs, S.

Paper Title Page
MOPC092 Single Particle Multi-turn Dynamics During Crystal Collimation 277
 
  • G. Robert-Demolaize, K. A. Drees, S. Peggs
    BNL, Upton, Long Island, New York
  • R. P. Fliller
    Fermilab, Batavia, Illinois
 
  As the increase in luminosity remains a high-profile issue for current and future accelerator projects, protecting superconducting magnets from beam induced quenches implies using state-of-the-art halo cleaning devices given the required beam intensities. In CERN's LHC case, a multi-stage collimation system is being set up so as to provide a halo cleaning efficiency up to 99.995%. In order to improve this system even further, US-LARP funded studies have started to appreciate the use of a silicon-based crystal as a primary target for the halo particles. Dedicated experiments have recently been performed in an SPS extraction line for a bent silicon crystal in case of single-pass particles. This article compares the published results of this experiment with simulations using established tracking codes. The goal is to better describe the main physics mechanisms involved in the beam-crystal interaction. A simple algorithm is then introduced to allow for fast tracking of the effect of a crystal on a high energy proton beam over many turns. The general feasibility of single particle, multi-turn crystal experiments at the SPS (CERN) and Tevatron (Fermilab) and their outline are discussed.  
MOPC129 Lattice without Transition Energy for the Future PS2 370
 
  • D. Trbojevic, S. Peggs
    BNL, Upton, Long Island, New York
  • Y. Papaphilippou, R. de Maria
    CERN, Geneva
 
  The Large Hadron Collider (LHC) will be commissioned very soon. Improvements of the LHC injection complex are considered in the upgrade possibilities. In the injection complex it is considered that the aging Proton Synchrotron (PS) would be replaced with a new fast cycling synchrotron PS2. The energy range would be from 5-50 GeV with a repetition rate of 0.3 Hz. This is a report on the PS2 lattice design using the Flexible Momentum Compaction (FMC) method*. The design is trying to fulfill many requirements: high compaction factor, racetrack shape with two long zero dispersion straight sections, circumference fixed to a value of 1346 meters (CPS2=15/77 CPS), using normal conducting magnets and avoiding the transition energy.

*D. Trbojevic et al. ”Design Method for High Energy Accelerator Without Transition Energy”, EPAC 90, Nice, June 12-16 (1990) pp. 1536-1538.

 
WEPD037 Nb3Sn Quadrupoles in the LHC IR Phase I Upgrade 2491
 
  • A. V. Zlobin, J. A. Johnstone, V. Kashikhin, N. V. Mokhov, I. L. Rakhno
    Fermilab, Batavia, Illinois
  • S. Peggs, G. Robert-Demolaize, P. Wanderer, R. de Maria
    BNL, Upton, Long Island, New York
 
  After some years of operation at nominal parameters, the LHC will be upgraded for higher luminosity. At the present time it is planned to perform the IR upgrade in two phases with the target luminosity for Phase I of ~2.5· 1034 cm-2s-1 and up to 1035 cm-2s-1 for Phase II. In Phase I the baseline 70-mm NbTi low-beta quadrupoles will nominally be replaced with larger aperture NbTi magnets and in Phase II with higher performance Nb3Sn magnets. U. S.-LARP is working on the development of large aperture high-performance Nb3Sn magnet technologies for the LHC Phase II luminosity upgrade. Recent progress also suggests the possibility of using Nb3Sn quadrupoles in the Phase I upgrade, improving the luminosity through an early demonstration of Nb3Sn magnet technology in a real accelerator environment. This paper discusses the possible hybrid optics layouts for Phase I upgrades with both NbTi and Nb3Sn quadrupoles, introducing magnet parameters and issues related to using Nb3Sn quadrupoles including magnet length and aperture limitations, field quality, operation margin, etc. Possible transition scenarios to Phase II are also discussed.  
THPP089 Gamma Transition Jump for PS2 3572
 
  • W. Bartmann, M. Benedikt, E. Métral, D. Möhl
    CERN, Geneva
  • S. Peggs
    BNL, Upton, Long Island, New York
 
  The PS2, which is proposed as a replacement for the existing ~50-year old PS accelerator, is presently considered to be a normal conducting synchrotron with an injection kinetic energy of 4 GeV and a maximum energy of 50 GeV. One of the possible lattices (FODO option) foresees crossing of transition energy near 10 GeV. Since many intensity dependent effects can take place in both the longitudinal and the transverse planes a fast jump of gamma transition is necessary in order to pass the non-adiabatic region rapidly. The aim of the present paper is on the one hand to scale the gamma transition jump, used since 1973 in the PS, to the projected PS2 and on the other hand based on these results the analysis of the implementation and feasibility of a gamma transition jump scheme in a conventional FODO lattice.