Author: Joshi, N.Y.
Paper Title Page
TUPC025 Calibration Errors in the Cavity Beam Position Monitor System at the ATF2 1051
 
  • F.J. Cullinan, S.T. Boogert, N.Y. Joshi, A. Lyapin
    JAI, Egham, Surrey, United Kingdom
 
  It has been shown at the Accelerator Test Facility at KEK, that it is possible to run a system of 37 cavity beam position monitors (BPMs) and achieve high working resolution. However, stability of the calibration constants (position scale and radio frequency (RF) phase) over a three/four week running period is yet to be demonstrated. During the calibration procedure, random beam jitter gives rise to a statistical error in the position scale and slow orbit drift in position and tilt causes systematic errors in both the position scale and RF phase. These errors are dominant and have been evaluated for each BPM. The results are compared with the errors expected after a tested method of beam jitter subtraction has been applied.  
 
TUPC161 Cavity Beam Position Monitor System for ATF2 1410
 
  • S.T. Boogert, R. Ainsworth, G.E. Boorman, S. Molloy
    Royal Holloway, University of London, Surrey, United Kingdom
  • A.S. Aryshev, Y. Honda, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  • F.J. Cullinan, N.Y. Joshi, A. Lyapin
    JAI, Egham, Surrey, United Kingdom
  • J.C. Frisch, D.J. McCormick, J. Nelson, T.J. Smith, G.R. White
    SLAC, Menlo Park, California, USA
  • A. Heo, E.-S. Kim, Y.I. Kim
    KNU, Deagu, Republic of Korea
 
  The Accelerator Test Facility 2 (ATF2) in KEK, Japan, is a prototype scaled demonstrator system for the final focus required for a future high energy lepton linear collider. The ATF2 beam-line is instrumented with a total of 41 high resolution C and S band resonant cavity beam position monitors (BPM) with associated mixer electronics and digitizers. In addition 4 high resolution BPMs have been recently installed at the interaction point, we briefly describe the first operational experience of these cavities in the ATF2 beam-line. The current status of the overall BPM system is also described, with a focus on operational techniques and performance.  
 
TUPC164 Position Determination of Closely Spaced Bunches using Cavity BPMs 1419
 
  • N.Y. Joshi, S.T. Boogert, F.J. Cullinan, A. Lyapin
    JAI, Egham, Surrey, United Kingdom
 
  Cavity Beam Position Monitor (BPM) systems with high-Q form a major part of precision position measurement diagnostics for linear accelerators with low emittance beam. Using cavity BPMs, the position resolution of less than 100 nm has been demonstrated in single bunch mode operation. In the case of closely spaced bunches, where the decay time of the cavity is comparable to the time separation between bunches, the BPM signal from a bunch is polluted by the signal induced from the previous bunches in the same bunch-train. This paper discuss our ongoing work to develop the methods to extract the position of the closely spaced bunches using cavity BPMs. A signal subtraction code is being developed to remove the signal pollution from previous bunches and to determine the individual bunch position. Another code has been developed to simulate the BPM data for the cross check. Performance of the code is studied on the experimental and simulated data. Application of the analysis techniques to the linear colliders, such as International Linear Collider (ILC) and Compact LInear Collider (CLIC), are briefly discussed.