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Presland, A.

Paper Title Page
MOPLS008 Beam Halo on the LHC TCDQ Diluter System and Thermal Load on the Downstream Superconducting Magnets 547
 
  • B. Goddard, R.W. Assmann, A. Presland, S. Redaelli, G. Robert-Demolaize, L. Sarchiapone, Th. Weiler, W.J.M. Weterings
    CERN, Geneva
 
  The moveable single-jawed graphite TCDQ diluter must be positioned very close to the circulating LHC beam in order to prevent damage to downstream components in the event of an unsynchronised beam abort. A two-jawed graphite TCS collimator forms part of the TCDQ system. The requirement to place the TCDQ and TCS jaws close to the beam means that the system can intercept a substantial beam halo load. Initial investigations indicated a worryingly high heat load on the Q4 coils. This paper presents the updated load cases, shielding and simulation geometry, and the results of simulations of the energy deposition in the TCDQ system and in the downstream superconducting Q4 magnet. The implications for the operation of the LHC are discussed.  
TUPLS012 Dynamic Stresses in the LHC TCDS Diluter from 7 TeV Beam Loading 1511
 
  • B. Goddard, A. Presland, W.J.M. Weterings
    CERN, Geneva
  • L. Massidda
    CRS4, PULA
 
  In the event of an unsynchronised beam abort, the MSD extraction septum of the LHC beam dumping system is protected from damage by the TCDS diluter. The simultaneous constraints of obtaining sufficient beam dilution while ensuring the survival of the TCDS make the design difficult, with high thermally induced dynamic stresses occurring in the material needed to attenuate the particle showers induced by the primary beam impact. In this paper, full 3D simulations are described where the worst-case beam loading has been used to generate the local temperature rise and to follow the resulting time evolution of the mechanical stresses. The results and the accompanying design changes for the TCDS, to provide an adequate performance margin, are detailed.  
TUPLS123 Design of the LHC Beam Dump Entrance Window 1792
 
  • R. Veness, B. Goddard, S.J. Mathot, A. Presland
    CERN, Geneva
  • L. Massidda
    CRS4, PULA
 
  7 TeV proton beams from the LHC are ejected through a 600 m long beam dump transfer line vacuum chamber to a beam dump block. The dump block is contained within an inert gas-filled vessel to prevent a possible fire risk. The dump vessel and transfer line are separated by a 600 mm diameter window, which must withstand both the static pressure load and thermal shock from the passage of the LHC beam. In a previous paper* the functional requirements and conceptual design of this window were outlined. This paper describes the analysis leading to the final design of the window. The choice of materials is explained and tests performed on the prototype window are summarized.

*A. Presland et al. "A large diameter entrance window for the LHC beam dump line". Proc. PAC 2005, 1698-1700.