Author: Burkhardt, H.
Paper Title Page
MOPWO027 Improved TEAPOT Method and Tracking with Thick Quadrupoles for the LHC and its Upgrade 945
  • H. Burkhardt, R. De Maria, M. Giovannozzi, T. Risselada
    CERN, Geneva, Switzerland
  The comparison between tracking with thick and thin lens models for the LHC have been studied. A widely-used method to generate thin models is based on the TEAPOT slicing, which, in the original implementation is limited in the number of slices. In this paper an improved method is presented, which overcomes some of the limitations of the original TEAPOT. The performance is analysed and the impact on numerical simulation of the dynamic aperture is evaluated, both for the LHC and its upgrade, HL-LHC.  
TUPFI036 Observation of Beam Instabilities with Very Tight Collimation 1424
  • H. Burkhardt, N. Mounet, T. Pieloni
    CERN, Geneva, Switzerland
  We report about the observation of instabilities in the LHC in special runs with high β* and very tight collimation down to 2 σ which increases the transverse impedance significantly. The losses appeared primarily on the highest intensity, non-colliding bunches which can be interpreted as evidence for insufficient Landau damping. We describe the beam conditions, observations and possible explanations for the observed effects.  
TUPFI037 Collimation Down to 2 Sigma in Special Physics Runs in the LHC 1427
  • H. Burkhardt, S. Jakobsen, S. Redaelli, B. Salvachua, G. Valentino
    CERN, Geneva, Switzerland
  We report on observations with collimation very close to the beam. Primary collimators were moved in small steps down to 2 σ from the beam axis to allow for measurements of very forward proton scattering in special high-beta runs in the LHC. We studied the reduction in intensity as a function of collimator position which provides information about the halo shape. After scraping at 2 σ, collimators were retracted to 2.5 σ. This allowed for measurements of very forward proton-proton scattering with roman pot detectors at 3 σ from the beam axis at acceptable background levels for about an hour. Good background conditions were restored by another scraping with primary collimators at 2 σ. Beam lifetimes and halo repopulation times were found to be sufficiently long to allow for several hours of data taking between scraping in a single LHC fill.  
TUPWO050 Commissioning and Operation at β* = 1000 m in the LHC 1982
  • H. Burkhardt, T. Persson, R. Tomás, J. Wenninger
    CERN, Geneva, Switzerland
  • S. Cavalier
    LAL, Orsay, France
  We have developed a special optics with a β* of 1000 m for two interaction regions (IR1 and IR5) in the LHC, to produce very low divergence beams required for elastic proton-proton scattering. We describe the design, commissioning and operation of this optics in the LHC. The β* of 1000 m was reached by de-squeezing the beams using 17 intermediate steps beyond the β* of 90 m, which had been the previous highest β* value reached in the LHC. The optics was measured and the beta beating globally corrected to a level of 10 per cent.