Author: Kotzian, G.
Paper Title Page
MOPO012 LHC Damper Beam Commissioning in 2010 505
 
  • W. Höfle, G. Kotzian, M. Schokker, D. Valuch
    CERN, Geneva, Switzerland
 
  The LHC transverse dampers were commissioned in 2010 with beam and their use at injection energy of 450 GeV, during the ramp and in collisions at 3.5 TeV for Physics have become part of the standard operations procedure. The system proved important to limit emittance blow-up at injection and maintain smaller than nominal emittances throughout the accelerating cycle. We describe the commissioning of the system step-by-step as done in 2010 and summarize its performance as achieved for proton as well as ion beams in 2010. Although its principle function is to keep transverse oscillations under control, the system has also been used as an exciter for abort gap cleaning and tune measurement. The dedicated beam position measurement system with its low noise properties provides additional possibilities for diagnostics.  
 
MOPO013 Suppression of Emittance Growth by Excited Magnet Noise with the Transverse Damper in LHC in Simulations and Experiment 508
 
  • W. Höfle, G. Arduini, R. De Maria, G. Kotzian, D. Valuch
    CERN, Geneva, Switzerland
  • V.A. Lebedev
    Fermilab, Batavia, USA
 
  The LHC transverse dampers initially build to control transverse instabilities are also a good remedy to suppress the oscillations causing emittance growth excited by electro-magnetic noises at the frequencies of betatron sidebands. To prevent the emittance growth excited by magnet noise using the damper this system has to have extremely low noise properties. The paper discusses simulation results on the effectiveness of the transverse feedback system to suppress such oscillations and the experimental results from a damper point of view as they were gained during the 2010 LHC run. Possible improvements in the damper system to enhance its effectiveness with respect to the suppression of emittance blow-up are also discussed.