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Bottura, L.

Paper Title Page
WEPCH048 Measurement and Modeling of Magnetic Hysteresis in the LHC Superconducting Correctors 2026
 
  • W. Venturini Delsolaro, L. Bottura, Y. C. Chaudhari, M. Karppinen
    CERN, Geneva
  • N.J. Sammut
    University of Malta, Faculty of Engineering, Msida
 
  The Large Hadron Collider, now under construction at CERN, relies heavily on superconducting magnets for its optics layout: besides the main magnets, almost all the correcting magnets are superconducting. Along with clear advantages, this brings about complications due to the effects of persistent currents in the superconducting filaments. Correcting magnets that trim key beam parameters or compensate field errors of the main magnets (among others those due to hysteresis), are in their turn hysteretic. The measured magnetic hysteresis and its possible influence on accelerator operation will be presented, in particular the real-time compensation of decay and snapback in the main magnets, and the reproducibility between runs. A detailed characterization of minor hysteresis loops is given, as well as degaussing cycles and modeling work.  
WEPLS100 Performance of LHC Main Dipoles for Beam Operation 2610
 
  • G. De Rijk, M. Bajko, L. Bottura, M.C.L. Buzio, V. Chohan, L. Deniau, P. Fessia, J. Garcia Perez, P. Hagen, J.-P. Koutchouk, J. Kozak, J. Miles, M. Missiaen, M. Modena, P. Pugnat, V. Remondino, L. Rossi, S. Sanfilippo, F. Savary, A.P. Siemko, N. Smirnov, A. Stafiniak, E. Todesco, D. Tommasini, J. Vlogaert, C. Vollinger, L. Walckiers, E.Y. Wildner
    CERN, Geneva
 
  At present about 75% of the main dipoles for the LHC have been manufactured and one of the three cold mass assemblers has already completed the production. More than two third of the 1232 dipoles needed for the tunnel have been tested and accepted. In this paper we mainly deal with the performance results: the quench behavior, the magnetic field quality, the electrical integrity quality and the geometry features will be summarized. The variations in performance associated with different cold mass assemblers and superconducting cable origins will be discussed.  
WEPLS103 The Field Description Model for the LHC Quadrupole Superconducting Magnets 2619
 
  • N.J. Sammut, L. Bottura, S. Sanfilippo
    CERN, Geneva
  • J. Micallef
    University of Malta, Faculty of Engineering, Msida
 
  The LHC control system requires an accurate forecast of the magnetic field and the multipole field errors to reduce the burden on the beam-based feed-back. The Field Description for the LHC (FIDEL) is the core of this forecast system and is based on the identification and physical decomposition of the effects that contribute to the total field in the magnet apertures. The effects are quantified using the data obtained from series magnetic measurements at CERN and they are consequently modelled empirically or theoretically depending on the complexity of the physical phenomena. This paper presents a description of the methodology used to model the field of the LHC magnets particularly focusing on the results obtained for the LHC Quadrupoles (MQ, MQM and MQY).  
WEPLS104 The Dependence of the Field Decay on the Powering History of the LHC Superconducting Dipole Magnets 2622
 
  • N.J. Sammut, L. Bottura, S. Sanfilippo
    CERN, Geneva
  • J. Micallef
    University of Malta, Faculty of Engineering, Msida
 
  The decay amplitude of the allowed multipoles in the LHC dipoles is expected to perturb the beam stability during the injection phase and is strongly dependent on the powering history of the magnet. The effect is particularly large for the pre-cycle nominal flat-top current and duration. With possible prospects of having different genres of cycles during the LHC operation, the powering history effect must be taken into account in the Field Description Model for the LHC (FIDEL) and must hence be corrected for during machine operation. This paper presents the results of the modelling of this phenomenon. We also discuss the statistic of magnetic measurements required to guarantee that the current history effect is predicted within the specified accuracy.