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Jonker, M.

Paper Title Page
WEPEB071 The CLIC Machine Protection 2860
 
  • M. Jonker, E.B. Holzer, S. Mallows, D. Manglunki, G. Morpurgo, Th. Otto, M. Sapinski, F. Tecker, J.A. Uythoven
    CERN, Geneva
 
 

The proposed Compact Linear Collider (CLIC) is based on a two-beam acceleration scheme. The energy of high intensity, low energy drive beams is extracted and transferred to low intensity, high energy main beams. Direct ionization loss by the beam particles is the principal damage mechanism. The total charge gives a single drive beam-train a damage potential that is two orders of magnitude above the level causing structural damage in copper. For the main beam, it is the extreme charge density due to the microscopic beam size that gives it a damage potential of four orders of magnitude above the safe level. The machine protection system has to cope with a wide variety of failures, from real time failures (RF breakdowns, kickers misfiring), to slow equipment failures, to beam instabilities (caused by e.g. temperature drifts, slow ground motions). This paper discusses the baseline for the CLIC machine protection system which is based on passive, active and permit based protection. As the permit based protection depends on the measured performance of the previous pulse, the bootstrap procedure with safe beams and stepwise increase in beam intensities, is also discussed.

 
WEPEB074 Requirements of CLIC Beam Loss Monitoring System 2869
 
  • M. Sapinski, B. Dehning, E.B. Holzer, M. Jonker, S. Mallows, Th. Otto
    CERN, Geneva
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire
 
 

The Compact Linear Collider (CLIC) is a proposed multi-TeV linear electron-positron collider being designed by a world-wide collaboration. It is based on a novel two-beam acceleration scheme in which two beams (drive and main beam) are placed in parallel to each other and energy is transferred from the drive beam to the main one. Beam losses on either of them can have catastrophic consequences for the machine because of high intensity (drive beam) or high energy and small emittance (main beam). In the framework of machine protection, a Beam Loss Monitoring system has to be put in place. This paper discusses the requirements for the beam loss system in terms of detector sensitivity, resolution, dynamic range and ability to distinguish losses originating from various sources. A particular attention is given to the two-beam module where the protection from beam losses is particularly challenging and important.

 
TUOAMH01 First Cleaning with LHC Collimators 1237
 
  • D. Wollmann, O. Aberle, G. Arnau-Izquierdo, R.W. Assmann, J.-P. Bacher, V. Baglin, G. Bellodi, A. Bertarelli, A.P. Bouzoud, C. Bracco, R. Bruce, M. Brugger, S. Calatroni, F. Caspers, F. Cerutti, R. Chamizo, A. Cherif, E. Chiaveri, P. Chiggiato, A. Dallocchio, R. De Morais Amaral, B. Dehning, M. Donze, A. Ferrari, R. Folch, P. Francon, P. Gander, J.-M. Geisser, A. Grudiev, E.B. Holzer, D. Jacquet, J.B. Jeanneret, J.M. Jimenez, M. Jonker, J.M. Jowett, Y. Kadi, K. Kershaw, L. Lari, J. Lendaro, F. Loprete, R. Losito, M. Magistris, M. Malabaila, A. Marsili, A. Masi, S.J. Mathot, M. Mayer, C.C. Mitifiot, N. Mounet, E. Métral, A. Nordt, R. Perret, S. Perrollaz, C. Rathjen, S. Redaelli, G. Robert-Demolaize, S. Roesler, A. Rossi, B. Salvant, M. Santana-Leitner, I. Sexton, P. Sievers, T. Tardy, M.A. Timmins, E. Tsoulou, E. Veyrunes, H. Vincke, V. Vlachoudis, V. Vuillemin, Th. Weiler, F. Zimmermann
    CERN, Geneva
  • I. Baishev, I.A. Kurochkin
    IHEP Protvino, Protvino, Moscow Region
  • D. Kaltchev
    TRIUMF, Vancouver
 
 

The LHC has two dedicated cleaning insertions: IR3 for momentum cleaning and IR7 for betatron cleaning. The collimation system has been specified and built with tight mechanical tolerances (e.g. jaw flatness ~ 40 μm) and is designed to achieve a high accuracy and reproducibility of the jaw positions. The practically achievable cleaning efficiency of the present Phase-I system depends on the precision of the jaw centering around the beam, the accuracy of the gap size and the jaw parallelism against the beam. The reproducibility and stability of the system is important to avoid the frequent repetition of beam based alignment which is currently a lengthy procedure. Within this paper we describe the method used for the beam based alignment of the LHC collimation system, its achieved accuracy and stability and its performance at 450GeV.

 

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