Author: Alemany-Fernandez, R.
Paper Title Page
WEPPR069 Measurements and Simulations of Transverse Coupled-Bunch Instability Rise Times in the LHC 3087
 
  • N. Mounet, R. Alemany-Fernandez, W. Höfle, D. Jacquet, V. Kain, E. Métral, L. Ponce, S. Redaelli, G. Rumolo, R. Suykerbuyk, D. Valuch
    CERN, Geneva, Switzerland
 
  In the current configuration of the LHC, multibunch instabilities due to the beam-coupling impedance would be in principle a critical limitation if they were not damped by the transverse feedback. For the future operation of the machine, in particular at higher bunch intensities and/or higher number of bunches, one needs to make sure the coupled-bunch instability rise times are still manageable by the feedback system. Therefore, in May 2011 experiments were performed to measure those rise times and compare them with the results obtained from the LHC impedance model and the HEADTAIL wake fields simulation code. At injection energy, agreement turns out to be very good, while a larger discrepancy appears at top energy.  
 
THPPP018 Operation of the LHC at High Luminosity and High Stored Energy 3767
 
  • J. Wenninger, R. Alemany-Fernandez, G. Arduini, R.W. Assmann, B.J. Holzer, E.B. Holzer, V. Kain, M. Lamont, A. Macpherson, G. Papotti, M. Pojer, L. Ponce, S. Redaelli, M. Solfaroli Camillocci, J.A. Uythoven, W. Venturini Delsolaro
    CERN, Geneva, Switzerland
 
  In 2011 the operation of the Large Hadron Collider LHC entered its first year of high luminosity production at a beam energy of 3.5 TeV. In the first months of 2011 the number of bunches was progressively increased to 1380, followed by a reduction of the transverse emittance, an increase of the bunch population and a reduction of the betatron function at the collision points. The performance improvements steps that were accumulated in 2011 eventually brought the peak luminosity to 3.6·1033 cm-2s−1. The integrated luminosity delivered to each of the high luminosity experiments amounted to 5.6 fb-1, a factor of 5 above the initial target defined in 2010. The operational experience with high intensity and high luminosity at the LHC will be presented here, together with the issues that had to be tackled on the road to high intensity and luminosity.