Author: Todesco, E.
Paper Title Page
WEEPPB014 The Magnetic Model of the LHC during the 3.5 TeV Run 2194
 
  • E. Todesco, N. Aquilina, M. Giovannozzi, M. Lamont, F. Schmidt, R.J. Steinhagen, M. Strzelczyk, R. Tomás
    CERN, Geneva, Switzerland
  • N.J. Sammut
    University of Malta, Information and Communication Technology, Msida, Malta
 
  The magnetic model of the LHC is based on a fit of the magnetic measurements through equations that model the field components (geometric, saturation, persistent) at different currents. In this paper we will review the main results related to the magnetic model during the run of the LHC in 2010-2011: with a top energy of 3.5 TeV, all components of the model but the saturation are visible. We first give an estimate of the reproducibility of the main components and multipolar errors as they can be deduced from beam measurements, i.e. orbit, tune, chromaticity, beta beating and coupling. We then review the main results relative to the decay at injection plateau, dependence on powering history, and snapback at the beginning of the ramp for both tune and chromaticity. We discuss the precision obtained in tracking the magnets during the ramp, where the persistent current components gradually disappear. We conclude by presenting the behaviour of the quadrupoles model during the squeeze. A list of the major changes implemented during the operation together with what are considered as the main open issues is given.  
 
TUPPC081 First Experimental Observations from the LHC Dynamic Aperture Experiment 1362
 
  • M. Giovannozzi, M. Albert, G.E. Crockford, S.D. Fartoukh, W. Höfle, E.H. Maclean, A. Macpherson, L. Ponce, S. Redaelli, H. Renshall, F. Roncarolo, R.J. Steinhagen, E. Todesco, R. Tomás, W. Venturini Delsolaro
    CERN, Geneva, Switzerland
  • R. Miyamoto
    BNL, Upton, Long Island, New York, USA
 
  Following intensive numerical simulations to compute the dynamic aperture for the LHC in the design phase, the successful beam commissioning and the ensuing beam operations opened the possibility of performing beam measurements of the dynamics aperture. In this paper the experimental set-up and the first observations based on the few experimental sessions performed will be presented and discussed in detail.