Author: Nosych, A.A.
Paper Title Page
TUPFI063 Electromagnetic Coupling between High Intensity LHC Beams and the Synchrotron Radiation Monitor Light Extraction System 1493
 
  • F. Roncarolo, W. Andreazza, A. Bertarelli, E. Bravin, F. Caspers, M. Garlaschè, A. Goldblatt, J-J. Gras, O.R. Jones, T. Lefèvre, E. Métral, A.A. Nosych, B. Salvant, G. Trad, R. Veness, C. Vollinger, M. Wendt
    CERN, Geneva, Switzerland
  
  The CERN LHC is equipped with two Syn­chro­tron Ra­di­a­tion Mon­i­tor sys­tems used to char­ac­terise trans­verse and lon­gi­tu­di­nal beam dis­tri­b­u­tions. Since the end of the 2011 LHC run the light ex­trac­tion sys­tem, based on a re­tractable mir­ror, has suf­fered de­for­ma­tion and me­chan­i­cal fail­ure that is cor­re­lated to the in­crease in beam in­ten­sity. Tem­per­a­ture probes have as­so­ci­ated these ob­ser­va­tions to a strong heat­ing of the mir­ror sup­port with a de­pen­dence on the lon­gi­tu­di­nal bunch length and shape, in­di­cat­ing the ori­gin as elec­tro­mag­netic cou­pling be­tween the beam and the struc­ture. This paper com­bines all this in­for­ma­tion with the aim of char­ac­ter­is­ing and im­prov­ing the sys­tem in view of its up­grade dur­ing the cur­rent LHC shut­down. Beam-based ob­ser­va­tions are pre­sented along with elec­tro­mag­netic and ther­mo­me­chan­i­cal sim­u­la­tions and com­ple­mented by lab­o­ra­tory mea­sure­ments, in­clud­ing the study of the RF prop­er­ties of dif­fer­ent mir­ror bulk and coat­ing ma­te­ri­als.  
 
TUPME032 Update on Beam Induced RF Heating in the LHC 1646
 
  • B. Salvant, O. Aberle, G. Arduini, R.W. Aßmann, V. Baglin, M.J. Barnes, W. Bartmann, P. Baudrenghien, O.E. Berrig, A. Bertarelli, C. Bracco, E. Bravin, G. Bregliozzi, R. Bruce, F. Carra, F. Caspers, G. Cattenoz, S.D. Claudet, H.A. Day, M. Deile, J.F. Esteban Müller, P. Fassnacht, M. Garlaschè, L. Gentini, B. Goddard, A. Grudiev, B. Henrist, S. Jakobsen, O.R. Jones, O. Kononenko, G. Lanza, L. Lari, T. Mastoridis, V. Mertens, N. Mounet, E. Métral, A.A. Nosych, J.L. Nougaret, S. Persichelli, A.M. Piguiet, S. Redaelli, F. Roncarolo, G. Rumolo, B. Salvachua, M. Sapinski, R. Schmidt, E.N. Shaposhnikova, L.J. Tavian, M.A. Timmins, J.A. Uythoven, A. Vidal, J. Wenninger, D. Wollmann, M. Zerlauth
    CERN, Geneva, Switzerland
  • H.A. Day
    UMAN, Manchester, United Kingdom
  • L. Lari
    IFIC, Valencia, Spain
  
  Since June 2011, the rapid in­crease of the lu­mi­nos­ity per­for­mance of the LHC has come at the ex­pense of in­creased tem­per­a­ture and pres­sure read­ings on spe­cific near-beam LHC equip­ment. In some cases, this beam in­duced heat­ing has caused de­lays whilie equip­ment cools down, beam dumps and even degra­da­tion of these de­vices. This con­tri­bu­tion gath­ers the ob­ser­va­tions of beam in­duced heat­ing at­trib­ut­able to beam cou­pling im­ped­ance, their cur­rent level of un­der­stand­ing and pos­si­ble ac­tions that are planned to be im­ple­mented dur­ing the long shut­down in 2013-2014.  
 
THPFI063 Development and Beam Tests of an Automatic Algorithm for Alignment of LHC Collimators with Embedded BPMs 3439
 
  • G. Valentino
    University of Malta, Information and Communication Technology, Msida, Malta
  • R.W. Aßmann
    DESY, Hamburg, Germany
  • R. Bruce, M. Gasior, D. Mirarchi, A.A. Nosych, S. Redaelli, B. Salvachua, N.J. Sammut
    CERN, Geneva, Switzerland
  
  Col­li­ma­tors with em­bed­ded Beam Po­si­tion Mon­i­tor (BPM) but­tons will be in­stalled in the LHC dur­ing the up­com­ing long shut­down pe­riod. Dur­ing the sub­se­quent op­er­a­tion, the BPMs will allow the col­li­ma­tor jaws to be kept cen­tered around the beam tra­jec­tory. In this man­ner, the best pos­si­ble beam clean­ing ef­fi­ciency and ma­chine pro­tec­tion can be pro­vided at un­prece­dented higher beam en­er­gies and in­ten­si­ties. A col­li­ma­tor align­ment al­go­rithm is pro­posed to cen­ter the jaws au­to­mat­i­cally around the beam. The al­go­rithm is based on suc­ces­sive ap­prox­i­ma­tion, as the BPM mea­sure­ments are af­fected by non-lin­ear­i­ties, which vary with the dis­tance be­tween op­po­site but­tons, as well as the dif­fer­ence be­tween the beam and the jaw cen­ters. The suc­cess­ful test re­sults, as well as some con­sid­er­a­tions for even­tual op­er­a­tion in the LHC are also pre­sented.