Author: Barschel, C.
Paper Title Page
MOPAB130 Cross-Calibration of the LHC Transverse Beam-Profile Monitors 437
 
  • R. Alemany-Fernández, F. Alessio, A. Alexopoulos, C. Barschel, F.S. Carlier, J.M. Coello de Portugal, M. Ferro-Luzzi, A. Garcia-Tabares, M. Hostettler, O. Karacheban, E.H. Maclean, R. Matev, T. Persson, P.K. Skowroński, R. Tomás, G. Trad, S. Vlachos, B. Würkner
    CERN, Geneva, Switzerland
  • G.R. Coombs
    EPFL, Lausanne, Switzerland
  • T.B. Hadavizadeh
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
  • M. Hofer
    TU Vienna, Wien, Austria
  • L. van Riesen-Haupt
    University of Oxford, Oxford, United Kingdom
 
  Calibration of a transverse beam profile monitor is of fundamental importance to guarantee the best possible accuracy and reliability of the instrument over time. In LHC the calibration standard for transverse-profile measurements are the wire scanners. Other profile monitors such as beam synchrotron light telescopes and interferometers are calibrated with respect to them. Additional information about single-bunch sizes can be obtained from beam-gas imaging in the LHCb vertex detector, from the transverse convolved beam sizes extracted from luminosity scans at the collision points, and from the evolution of the luminous-region parameters as reconstructed by ATLAS and CMS inner tracker detectors during such scans. For the first time in LHC, a dedicated cross-calibration of all the above-mentioned systems was carried out with beam in 2016. Additionally, dedicated optics measurements were also performed in order to determine with the highest possible accuracy the amplitude function at the interaction points and at the position of the profile monitors. Results of these measurements are presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB130  
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MOPAB131 Transverse Emittance Measurements Using LHCb's Beam-Gas Interactions 441
 
  • T.B. Hadavizadeh
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
  • R. Alemany-Fernández, F. Alessio, C. Barschel, G.R. Coombs, M. Ferro-Luzzi, R. Matev
    CERN, Geneva, Switzerland
 
  Measurements of the transverse beam emittance are of great importance at particle accelerators such as the LHC in order to monitor, understand and improve the performance of the machine. A number of profile monitors at the LHC are capable of measuring the transverse emittance from a range of different processes including wire scanners and beam synchrotron light monitors, each having advantages and shortcomings. It is possible additionally to measure the beam profiles using interaction vertices reconstructed in LHCb's vertex locator (Velo). Interactions between colliding beam particles and between beam particles and residual gas nuclei are used to build up a picture of the beam profiles. To guarantee the reliability and quality of the different emittance measurements, a dedicated cross-calibration was performed during a machine development period in October 2016. The results obtained with the LHCb Velo during this cross-calibration are presented here.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB131  
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TUOAB1 First LHC Transverse Beam Size Measurements With the Beam Gas Vertex Detector 1240
SUSPSIK078   use link to see paper's listing under its alternate paper code  
 
  • A. Alexopoulos, C. Barschel, E. Bravin, G. Bregliozzi, N. Chritin, B. Dehning, M. Ferro-Luzzi, M. Giovannozzi, R. Jacobsson, L.K. Jensen, O.R. Jones, V. Kain, R. Matev, M.N. Rihl, V. Salustino Guimaraes, R. Veness, S. Vlachos, B. Würkner
    CERN, Geneva, Switzerland
  • A. Bay, F. Blanc, S. Gianì, O. Girard, G.J. Haefeli, P. Hopchev, A. Kuonen, T. Nakada, O. Schneider, M. Tobin, Q.D. Veyrat, Z. Xu
    EPFL, Lausanne, Switzerland
  • R. Greim, W. Karpinski, T. Kirn, S. Schael, A. Schultz von Dratzig, G. Schwering, M. Wlochal
    RWTH, Aachen, Germany
 
  The Beam Gas Vertex detector (BGV) is an innovative beam profile monitor based on the reconstruction of beam-gas interaction vertices which is being developed as part of the High Luminosity LHC project. Tracks are identified using several planes of scintillating fibres, located outside the beam vacuum chamber and perpendicular to the beam axis. The gas pressure in the interaction volume is adjusted such as to provide an adequate trigger rate, without disturbing the beam. A BGV demonstrator monitoring one of the two LHC beams was fully installed and commissioned in 2016. First data and beam size measurements show that the complete detector and data acquisition system is operating as expected. The BGV operating parameters are now being optimised and the reconstruction algorithms developed to produce accurate and fast reconstruction on a CPU farm in order to provide real time beam profile measurements to the LHC operators.  
slides icon Slides TUOAB1 [3.456 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUOAB1  
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