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Steinhagen, R.J.

Paper Title Page
MOOCRA01 The Magnetic Model of the LHC in the Early Phase of Beam Commissioning 55
 
  • E. Todesco, N. Aquilina, B. Auchmann, L. Bottura, M.C.L. Buzio, R. Chritin, G. Deferne, L. Deniau, L. Fiscarelli, J. Garcia Perez, M. Giovannozzi, P. Hagen, M. Lamont, G. Montenero, G.J. Müller, S. Redaelli, RV. Remondino, F. Schmidt, R.J. Steinhagen, M. Strzelczyk, M. Terra Pinheiro Fernandes Pereira, R. Tomás, W. Venturini Delsolaro, J. Wenninger, R. Wolf
    CERN, Geneva
  • N.J. Sammut
    University of Malta, Faculty of Engineering, Msida
 
 

The relation between field and current in each family of the Large Hadron Collider magnets is modeled with a set of empirical equations (FiDeL) whose free parameters are fitted on magnetic measurements. They take into account of residual magnetization, persistent currents, hysteresis, saturation, decay and snapback during initial part of the ramp. Here we give a first summary of the reconstruction of the magnetic field properties based on the beam observables (orbit, tune, coupling, chromaticity) and a comparison with the expectations based on the large set of magnetic measurements carried out during the 5-years-long production. The most critical issues for the machine performance in terms of knowledge of the relation magnetic field vs current are pinned out.

 

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Slides

 
MOPE062 Continuous Measurement and Control of Beta-Beating in the LHC 1119
 
  • R.J. Steinhagen, A. Boccardi, E. Calvo Giraldo, M. Gasior, J.L. Gonzalez, O.R. Jones
    CERN, Geneva
 
 

The beta function has a fundamental impact on the LHC performance and on the functioning of its machine protection and collimation systems. A new beta-beat diagnostic system, prototyped at the SPS, has been used to verify the time-dependent variations of the LHC lattice with unprecedented 1% beta-beta resolution and at a measurement bandwidth of about 1 Hz.

 
WEPEB041 Commissioning and Initial Performance of the LHC Beam Based Feedback Systems 2779
 
  • R.J. Steinhagen, A. Boccardi, A.C. Butterworth, E. Calvo Giraldo, R. Denz, M. Gasior, J.L. Gonzalez, S. Jackson, L.K. Jensen, O.R. Jones, Q. King, G. Kruk, M. Lamont, S.T. Page, J. Wenninger
    CERN, Geneva
 
 

The LHC deploys a comprehensive suite of beam-based feedbacks for safe and reliable machine operation. This contribution summarises the commissioning and early results of the LHC feedback control systems on orbit, tune, chromaticity, and energy. Their performance – strongly linked to the associated beam instrumentation, external beam perturbation sources and optics uncertainties – is evaluated and compared with the feedback design assumptions.