Author: Bruce, R.
Paper Title Page
MOPPD062 Aperture Measurements in the LHC Interaction Regions 508
  • S. Redaelli, M.C. Alabau Pons, R.W. Assmann, R. Bruce, M. Giovannozzi, G.J. Müller, M. Pojer, J. Wenninger
    CERN, Geneva, Switzerland
  The aperture of the LHC interaction regions is crucial for the LHC performance because it determines the smaller β* that can be achieved. The aperture has been measured at a maximum energy of 3.5 TeV and at different β* values, following optimized procedure to allow safe measurements at high energy. In this paper, the results of these aperture measurements, which are used as a reference for β* reach and crossing scheme estimates at the LHC interaction points, are presented.  
MOPPD078 Accelerator Physics Study on the Effects from an Asynchronous Beam Dump in the LHC Experimental Region Collimators 547
  • L. Lari, R.W. Assmann, V. Boccone, R. Bruce, F. Cerutti, A. Mereghetti, A. Rossi, V. Vlachoudis
    CERN, Geneva, Switzerland
  • A. Faus-Golfe, L. Lari
    IFIC, Valencia, Spain
  Funding: This work has been carried out through of the European Coordination for Accelerator Research and Development (EuCARD), co-sponsored by EU 7th Framework Program.
Asynchronous beam aborts at the LHC are to be expected once per year. Accelerator physics studies of asynchronous dumps have been performed at different beam energies and beta-stars. The loss patterns are analyzed in order to identify the losses in particular on the Phase 1 Tertiary Collimators (TCT), since their Tungsten jaw insert has a low damage threshold with respect to the loss load expected. Settings for the tilt angle of the TCTs are discussed with the aim of reducing the thermal loads on the TCT themselves.
TUPPR098 Comparison of LHC Collimator Beam-Based Alignment Centers to BPM-Interpolated Centers 2062
  • G. Valentino, N.J. Sammut
    University of Malta, Information and Communication Technology, Msida, Malta
  • R.W. Assmann, R. Bruce, G.J. Müller, S. Redaelli, A. Rossi, G. Valentino
    CERN, Geneva, Switzerland
  • L. Lari
    IFIC, Valencia, Spain
  The beam centers at the Large Hadron Collider collimators are determined by beam-based alignment, where both jaws of a collimator are moved in separately until a loss spike is detected on a Beam Loss Monitor downstream. Orbit drifts of more than a few hundred micrometers cannot be tolerated, as they would reduce the efficiency of the collimation system. Beam Position Monitors (BPMs) are installed at various locations around the LHC ring, and a linear interpolation of the orbit can be obtained at the collimator positions. In this paper, the results obtained from beam-based alignment are compared with the orbit interpolated from the BPM data throughout the 2011 LHC proton run. The stability of the orbit determined by collimator alignment during the run is evaluated.