Author: Bett, D.R.
Paper Title Page
MOPWA057 Development of a High-resolution, Broad-band, Stripline Beam Position Monitoring System 804
  • G.B. Christian, D.R. Bett, N. Blaskovic Kraljevic, P. Burrows, M.R. Davis, Y.I. Kim, C. Perry
    JAI, Oxford, United Kingdom
  • R. Apsimon, B. Constance
    CERN, Geneva, Switzerland
  • P. Burrows, C. Perry
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
  • J. Resta
    IFIC, Valencia, Spain
  A low-latency, sub-micron resolution stripline beam position monitoring system has been developed and tested with beam at the KEK Accelerator Test Facility, where it has been used as part of a feedback system for beam stabilisation. The fast analogue front-end signal processor is based on a single-stage down-mixer and is combined with an FPGA-based system for digitisation and feedback control. A resolution as low as 400 nm has been demonstrated for beam intensities of ~1 nC, with single-pass beam. The latest results of recent modifications to balance the input path lengths to the processor will be discussed. These modifications compensate for the inherent phase sensitivity of the processors, and hence improve the intrinsic resolution, without the need for offline correction. Modifications to the FPGA firmware will also be described, to allow for flexible operation with variable system-synchronous data acquisition at up to 400 MHz, with up to nine data channels of 13-bit width, and a nominal record length of 1 KS/channel/pulse (extensible to a total record length of 120 KS per pulse, for example, for use with long bunch trains or wide-band multi-turn measurements in storage rings).  
MOPWA058 Cavity Beam Position Monitor at Interaction Point Region of Accelerator Test Facility 2 807
  • Y.I. Kim, D.R. Bett, N. Blaskovic Kraljevic, P. Burrows, G.B. Christian, M.R. Davis, A. Lyapin
    JAI, Egham, Surrey, United Kingdom
  • S.T. Boogert
    Royal Holloway, University of London, Surrey, United Kingdom
  • J.C. Frisch, D.J. McCormick, J. Nelson, G.R. White
    SLAC, Menlo Park, California, USA
  • Y. Honda, T. Tauchi, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  Nanometre resolution cavity beam position monitors (BPMs) have been developed to measure the beam position and linked to a feedback system control the beam position stability within few nanometres in the vertical direction at the focus, or interaction point (IP), of Accelerator Test Facility 2 (ATF2). In addition, for feedback applications a lower-Q and hence faster decay time system is desirable. Two IPBPMs have been installed inside of IP chamber at the ATF2 focus area. To measure the resolution of IPBPMs two additional C-band cavity BPMs have been installed one upstream and one downstream of the IP. One cavity BPM has been installed at an upstream image point of IP. The performance of the BPMs is discussed and the correlation between IP and image point positions is presented along with a discussion of using these BPMs for position stabilisation at the IP.  
WEPME053 Latest Performance Results from the FONT 5 Intra Train Beam Position Feedback System at ATF 3049
  • M.R. Davis, D.R. Bett, N. Blaskovic Kraljevic, P. Burrows, G.B. Christian, Y.I. Kim, C. Perry
    JAI, Oxford, United Kingdom
  • R. Apsimon, B. Constance, A. Gerbershagen
    CERN, Geneva, Switzerland
  A prototype ultra-fast beam-based feedback system for deployment in single-pass beamlines, such as a future lepton collider (ILC or CLIC) or a free-electron laser, has been fabricated and is being tested in the extraction and final focus lines of the Accelerator Test Facility (ATF) at KEK. FONT5 is an intra-train feedback system for stabilising the beam orbit via different methods: a position and angle feedback correction in the extraction line or a vertical feedforward correction applied at the interaction point (IP) . Two systems comprise three stripline beam position monitors (BPMs) and two stripline kickers in the extraction line, two cavity BPMs and a stripline kicker at the IP, a custom FPGA-based digital processing board, custom kicker-drive amplifiers and low-latency analogue front-end BPM processors. Latest results from the experiment are presented. These include beam position correction in the extraction line, as well as preliminary results of beam correction at the IP.