Keyword: brightness
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MOP248 Brightness Evolution for LHC Beams during the 2012 Run emittance, injection, luminosity, extraction 170
 
  • M. Kuhn
    Uni HH, Hamburg, Germany
  • G. Arduini, J.F. Comblin, A. Guerrero, V. Kain, B. Mikulec, F. Roncarolo, M. Sapinski, M. Schaumann, R. Steerenberg
    CERN, Geneva, Switzerland
 
  One of the reasons for the remarkable achievements of the LHC is the excellent performance of the LHC injector chain. The evolution of the brightness in the injectors and at LHC collision in 2011 and 2012 is discussed. During certain run periods, the brightness from the beam provided by the injectors was lower than usual. Some of the issues have been identified so far and will be reported. The latest results on emittance blow-up investigations through the 2012 LHC cycle will also be presented and compared to the 2011 data. Possible implications for LHC upgrade scenarios will be mentioned.  
 
MOP250 Colliding High Brightness Beams in the LHC emittance, beam-beam-effects, proton, luminosity 180
 
  • T. Pieloni, X. Buffat, R. Giachino, W. Herr, E. Métral, G. Papotti
    CERN, Geneva, Switzerland
 
  The CERN-LHC is a high energy particle collider, where intense proton bunches are brought into collision. In order to achieve optimum performance, the bunches must have a high brightness, leading to strong and significant beam-beam effects. Experimental tests during the first two years of its operation have shown that beams with very high brightness can be collided head-on without detrimental effects on the beam dynamics. Such head-on collisions are therefore not expected to limit the LHC performance. Long range beam-beam interactions dominate the adverse effects on the dynamics but can profit from an increased beam brightness, in particular from small emittances. We summarize the experimental results and compare with the theoretical expectations. This allows to optimize the performance for future operation and a definition of promising upgrade scenarios.  
 
WEO1A02 LHC Impedance Model: Experience with High Intensity Operation in the LHC impedance, octupole, injection, damping 349
 
  • B. Salvant, O. Aberle, G. Arduini, R.W. Aßmann, V. Baglin, M.J. Barnes, P. Baudrenghien, A. Bertarelli, C. Bracco, R. Bruce, X. Buffat, F. Carra, F. Caspers, G. Cattenoz, S.D. Claudet, H.A. Day, J. Esteban Müller, M. Garlaschè, L. Gentini, B. Goddard, A. Grudiev, B. Henrist, W. Herr, S. Jakobsen, R.J. Jones, G. Lanza, L. Lari, T. Mastoridis, N. Mounet, E. Métral, A.A. Nosych, J.L. Nougaret, S. Persichelli, T. Pieloni, A.M. Piguiet, S. Redaelli, F. Roncarolo, G. Rumolo, B. Salvachua, M. Sapinski, E.N. Shaposhnikova, L.J. Tavian, M.A. Timmins, J.A. Uythoven, A. Vidal, R. Wasef, D. Wollmann
    CERN, Geneva, Switzerland
  • A.V. Burov
    Fermilab, Batavia, USA
  • S.M. White
    BNL, Upton, Long Island, New York, USA
 
  The CERN Large Hadron Collider (LHC) is now in luminosity production mode and has been pushing its performance in the past months by increasing the proton beam brightness, the collision energy and the machine availability. As a consequence, collective effects have started to become more and more visible and have effectively slowed down the performance increase of the machine. Among these collective effects, the interaction of brighter LHC bunches with the longitudinal and transverse impedance of the machine has been observed to generate beam induced heating and transverse instabilities since 2010. This contribution reviews the current LHC impedance model obtained from theory, simulations and bench measurements as well as a selection of measured effects with the LHC beam.  
slides icon Slides WEO1A02 [7.991 MB]