• R.W. Assmann, G. Bellodi, J.M. Jowett, E. Métral, Th. Weiler
  CERN, Geneva
• L. Keller, T.W. Markiewicz
  SLAC, Menlo Park, California

The LHC collimation system is implemented in phases, in view of the required extrapolation by 2-3 orders of magnitude beyond Tevatron and HERA experience in stored energy. All available simulations predict that the LHC proton beam intensity with the "phase 1" collimation system may be limited by the impedance of the collimators or cleaning efficiency. Maximum efficiency requires collimator materials very close to the beam, generating the dominant resistive impedance in the LHC. Above a certain intensity the beam is unstable. On the other hand, even if collimators are set very close to the beam, the achievable cleaning efficiency is predicted to be inadequate, requiring either beam stability beyond specifications or reduced intensity. The accelerator physics concept for upgrading cleaning efficiency, for both proton and heavy ion beams, and reducing collimator-related impedance is described. Besides the "phase 2" secondary collimators, new collimators are required in a few super-conducting regions.

• F. Zimmermann, F. Bordry, H.-H. Braun, O.S. Brüning, H. Burkhardt, A.L. Eide, R. Garoby, B.J. Holzer, J.M. Jowett, T.P.R. Linnecar, K.H. Meß, J.A. Osborne, L. Rinolfi, D. Schulte, R. Tomás, J. Tuckmantel, A. Vivoli, A. de Roeck
  CERN, Geneva
• H. Aksakal
  N.U, Nigde
• S. Chattopadhyay, J.B. Dainton
  Cockcroft Institute, Warrington, Cheshire
• A.K. Çiftçi
  Ankara University, Faculty of Sciences, Tandogan/Ankara
• M. Klein
  The University of Liverpool, Liverpool
• T. Omori, J. Urakawa
  KEK, Ibaraki
• S. Sultansoy
  TOBB ETU, Ankara
• F.J. Willeke
  BNL, Upton, Long Island, New York

Sub-atomic physics at the energy frontier probes the structure of the fundamental quanta of the Universe. The Large Hadron Collider (LHC) at CERN opens for the first time the “terascale” (TeV energy scale) to experimental scrutiny, exposing the physics of the Universe at the sub-attometric (~10^-19 m, 10^-10 as) scale. The LHC will also take the science of nuclear matter to hitherto unparalleled energy densities (low-x physics). The hadron beams, protons or ions, in the LHC underpin this horizon, and also offer new experimental possibilities at this energy scale. A Large Hadron electron Collider, LHeC, in which an electron (positron) beam of energy (70 to 140 GeV) is in collision with one of the LHC hadron beams, makes possible terascale lepton-hadron physics. The LHeC is presently being evaluated in the form of two options, “ring-ring” and “linac-ring”, either of which operate simultaneously with pp or ion-ion collisions in other LHC interaction regions. Each option takes advantage of recent advances in radio-frequency, in linear acceleration, and in other associated technologies, to achieve ep luminosity as large as 10³³ cm^-2s^-1.

Slides