Author: Gallilee, M.A.
Paper Title Page
TUPWA042 Lessons Learned and Mitigation Measures for the CERN LHC Equipment with RF Fingers 1802
  • E. Métral, O. Aberle, R.W. Aßmann, V. Baglin, M.J. Barnes, O.E. Berrig, A. Bertarelli, G. Bregliozzi, S. Calatroni, F. Carra, F. Caspers, H.A. Day, M. Ferro-Luzzi, M.A. Gallilee, C. Garion, M. Garlaschè, A. Grudiev, J.M. Jimenez, O.R. Jones, O. Kononenko, R. Losito, J.L. Nougaret, V. Parma, S. Redaelli, B. Salvant, P.M. Strubin, R. Veness, C. Vollinger, W.J.M. Weterings
    CERN, Geneva, Switzerland
  Beam-induced RF heating has been observed in several LHC components when the bunch/beam intensity was increased and/or the bunch length reduced. In particular eight bellows, out of the ten double-bellows modules present in the machine in 2011, were found with the spring, which should keep the RF fingers in good electrical contact with the central insert, broken. Following these observations, the designs of all the components of the LHC equipped with RF fingers have been reviewed. The lessons learnt and mitigation measures are presented in this paper.  
THPFI057 Development of Vacuum Chamber in Low Z Material 3421
  • C. Garion, P. Costa Pinto, M.A. Gallilee, J. Perez Espinos
    CERN, Geneva, Switzerland
  Highly transparent vacuum chambers are more and more required in high energy particle physics. In particular, vacuum chambers in the experiments should be as transparent as possible to minimize the background to the detectors while reducing also the material activation. Beryllium is, so far, the most performing material for this application, but it presents some drawbacks such as brittleness, manufacturing issues, toxic hazard, high cost and low availability. A development work to obtain alternative material to the beryllium with similar performance is being carried out at CERN. Three categories have been defined and considered: raw bulk material, material and structural composites. Main requirements are the vacuum compatibility: leak tightness, low outgassing rate, temperature resistance (in the range 200-230 °C), transparency, and mechanical stiffness and strength. Carbon is the element with the lowest atomic number after beryllium and that is appropriate for this application. Therefore carbon based materials have been considered in a variety of options. In this paper, several technologies are presented and discussed. Results of preliminary tests on samples are also shown.