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Mahner, E.

Paper Title Page
MPPP031 The CERN-SPS Experiment on Microwave Transmission Through the Beam Pipe 2212
 
  • T. Kroyer, T. Kroyer
    TU Vienna, Vienna
  • F. Caspers, E. Mahner
    CERN, Geneva
  
  Funding: Ministry for Education, Science and Culture, Austria.

In the CERN SPS microwave transmission measurements through beampipe sections with a length of 30 m and 7 m meter respectively have been carried out in the frequency range 2-4 GHz since spring 2003. Here we report on new results obtained with improved measurement techniques during the 2004 run. Observation techniques include a fast real time scope, spectrum analyser IF and video output signal registration and baseband signal observation using a PC soundcard. The unexpected beam induced amplitude modulation has been confirmed on all kinds of available beams including single bunches. It was found that there is a correlation between the amount of beam induced signal attenuation and the beam losses registered by external scintillators. Potential theoretical models are discussed.

 
FPAE070 A Collimation Scheme for Ions Changing Charge State in the LEIR Ring 3816
 
  • J. Pasternak, C.B. Bal, C. Carli, M. Chanel, E. Mahner
    CERN, Geneva
  
  Avalanche-like pressure rise and an associated decrease of the beam lifetime, caused by (i) beam loss due to charge exchange interactions with rest gas molecules and (ii) ion impact induced outgassing, is a potential limitation for heavy ion accelerators operating at low energy. Capture of electrons from the electron cooler is another source of ion losses and thus, of pressure rise. The vacuum system of the LEIR ring has to be upgraded to reach the dynamical vacuum pressure in the low 10-12 Torr range necessary to reach design performance. A collimation system to intercept lost ions by absorber blocksmade of low beam induced outgassing material will be installed. This paper reviews the collimation scheme and simulations of beam loss patterns around the ring.  
RPPE005 Ions for LHC: Beam Physics and Engineering Challenges 946
 
  • S. Maury, M.-E. Angoletta, V. Baggiolini, A. Beuret, A. Blas, J. Borburgh, H.-H. Braun, C. Carli, M. Chanel, T. Fowler, S.S. Gilardoni, M. Gourber-Pace, S. Hancock, C.E. Hill, M. Hourican, J.M. Jowett, K. Kahle, D. Kuchler, E. Mahner, D. Manglunki, M. Martini, M.M. Paoluzzi, J. Pasternak, F. Pedersen, U. Raich, C. Rossi, J.-P. Royer, K. Schindl, R. Scrivens, L. Sermeus, E.N. Shaposhnikova, G. Tranquille, M. Vretenar, Th. Zickler
    CERN, Geneva
  
  The first phase of the heavy ion physics program at the LHC aims to provide lead-lead collisions at energies of 5.5 TeV per colliding nucleon pair and ion-ion luminosity of 1027 cm-2s-1. The transformation of CERN’s ion injector complex (Linac3-LEIR-PS-SPS) presents a number of beam physics and engineering challenges. Conversion of the Low Energy Antiproton Ring (LEAR) to a Low Energy Ion Ring (LEIR) is under way: the high-current electron cooling system, novel broad-band RF cavities and vacuum equipment to achieve 10-12 mbar are the major challenges. Commissioning of LEIR with beam will start in the middle of 2005. Major hardware changes in Linac3 include the installation of the new ECR ion source and of the energy ramping cavity. The PS will have a new injection system and RF gymnastics. A stripping insertion between PS and SPS must not disturb the proton operation. In the LHC itself, there are fundamental performance limitations due to various beam loss mechanisms. To study these without risk of damage there will be an initial period of operation with a reduced number of nominal intensity bunches. While reducing the work required to commission the LHC with ions in 2008, this will still enable early physics discoveries.