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.