Author: Baglin, V.
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MOPMR027 Employing Beam-Gas Interaction Vertices for Transverse Profile Measurements 296
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  • M.N. Rihl, A. Alexopoulos, V. Baglin, C. Barschel, E. Bravin, G. Bregliozzi, N. Chritin, B. Dehning, M. Ferro-Luzzi, C. Gaspar, M. Giovannozzi, R. Jacobsson, L.K. Jensen, O.R. Jones, N.J. Jurado, V. Kain, M. Kuhn, B. Luthi, P. Magagnin, R. Matev, N. Neufeld, J. Panman, V. Salustino Guimaraes, B. Salvant, R. Veness, S. Vlachos
    CERN, Geneva, Switzerland
  • A. Bay, F. Blanc, S. Gianì, G.J. Haefeli, P. Hopchev, T. Nakada, B. Rakotomiaramanana, O. Schneider, M. Tobin, Q.D. Veyrat, Z. Xu
    EPFL, Lausanne, Switzerland
  • R. Greim, W. Karpinski, T. Kirn, S. Schael, G. Schwering, M. Wlochal, A. von Dratzig
    RWTH, Aachen, Germany
  Interactions of high-energy beam particles with residual gas offer a unique opportunity to measure the beam profile in a non-intrusive fashion. Such a method was successfully pioneered* at the LHCb experiment using a silicon microstrip vertex detector. During the recent Large Hadron Collider shutdown at CERN, a demonstrator Beam-Gas Vertexing system based on eight scintillating-fibre modules was designed**, constructed and installed on Ring 2 to be operated as a pure beam diagnostics device. The detector signals are read out and collected with LHCb-type front-end electronics and a DAQ system consisting of a CPU farm. Tracks and vertices will be reconstructed to obtain a beam profile in real time. Here, first commissioning results are reported. The advantages and potential for future applications of this technique are discussed.
* LHCb collaboration, Journal of Instrumentation, 9, P12005
** P. Hopchev in Proc. of IPAC 2014, June 15-20, 2014, Dresden Germany
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR027  
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THPMY007 Vacuum Performance of Amorphous Carbon Coating at Cryogenic Temperature with Presence of Proton Beams 3663
  • R. Salemme, V. Baglin, G. Bregliozzi, P. Chiggiato
    CERN, Geneva, Switzerland
  Amorphous carbon (a-C) coating is the baseline electron multipacting mitigation strategy proposed for the Inner Triplets (IT) in the High Luminosity upgrade of the Large Hadron Collider (HL-LHC). As of 2014, the COLD bore EXperiment (COLDEX) is qualifying the performance of a-C coating at cryogenic temperature in a LHC type cryogenic vacuum system. In this paper, the experimental results following a cryogenic vacuum characterization of a-C coating in the 5 to 150 K temperature range are reviewed. We discuss the dynamic pressure rise, gas composition, dissipated heat load and electron activity observed within an accumulated beam time of 9 Ah. The results of dedicated experiments including pre-adsorption of different gas species (H2, CO) on the a-C coating are discussed. Based of phenomenological modeling, up-to-date secondary emission input parameters for a-C coatings are retrieved for electron cloud build-up simulations. Finally, first implications for the HL-LHC ITs design are drawn.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMY007  
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