Author: Terunuma, N.
Paper Title Page
MOPC27 Cavity Beam Position Monitor System for ATF2 120
  • S.T. Boogert
    Royal Holloway, University of London, Surrey, United Kingdom
  • S.T. Boogert, F.J. Cullinan, Y.I. Kim, A. Lyapin, J. Snuverink
    JAI, Egham, Surrey, United Kingdom
  • T. Tauchi, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  • G.R. White
    SLAC, Menlo Park, California, USA
  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 38 C- and S- band resonant cavity beam position monitors (CBPM) with associated mixer electronics and digitizers. The current status of the BPM system is described, including a study of the CBPM performance over a three week period, including systematic effects such as charge, bunch length and beam offset dependence. The BPM system is routinely used for beam based alignment, wakefield kick measurements and dispersion measurements, the operational experience and example measurements are also reported.  
MOPF16 Sub-Micrometre Resolution Laserwire Transverse Beam Size Measurement System 243
  • L.J. Nevay
    JAI, Egham, Surrey, United Kingdom
  • A.S. Aryshev, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  • S.T. Boogert, P. Karataev, K.O. Kruchinin
    Royal Holloway, University of London, Surrey, United Kingdom
  • L. Corner, R. Walczak
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
  The laserwire system at the Accelerator Test Facility 2 (ATF2) is a transverse beam profile measurement system capable of measuring a micrometre-size electron beam. We present recent results demonstrating a measured vertical size of 1.16 ± 0.06 μm and a horizontal size of 110.1 ± 3.8 μm. Due to the high aspect ratio of the electron beam, the natural divergence of the tightly focussed laser beam across the electron beam width requires the use of the full overlap integral to deconvolve the scans. For this to be done accurately, the propagation of the 150 mJ, 167 ps long laser pulses was precisely measured at a scaled virtual interaction point.  
TUPC22 Cavity Beam Position Monitor in Multiple Bunch Operation for the ATF2 Interaction Point Region 419
  • Y.I. Kim, D.R. Bett, N. Blaskovic Kraljevic, S.T. Boogert, P. Burrows, G.B. Christian, M.R. Davis, A. Lyapin, C. Perry
    JAI, Oxford, 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
  The Accelerator Test Facility 2 (ATF2) at KEK, Japan, is a scaled test beam line for the international linear collider (ILC) final focus system. There are two goals: firstly, to demonstrate focusing to 37 nm vertical beam size; secondly, to achieve a few nanometer level beam orbit stability at the focus point (the Interaction Point (IP)) in the vertical plane. High-resolution beam position monitors around the IP area (IPBPMs) have been developed in order to measure the electron beam position in that region with a resolution of a few nanometers in the vertical plane. Currently, the standard operation mode at ATF2 is single bunch, however, multiple bunch operation with a bunch spacing similar to the one foreseen for the ILC (around 300 ns) is also possible. IPBPMs have a low Q value resulting in a decay time of about 30 ns, and so should be able to measure the beam position of individual bunches without any significant performance degradation. The IPBPMs in the ATF2 extraction beam line have been tested in multibunch regime. This paper analyses the signals, processing methods and results for this mode.  
poster icon Poster TUPC22 [1.050 MB]  
WEAL2 Extremely Low Emittance Beam Size Diagnostics with Sub-Micrometer Resolution Using Optical Transition Radiation 615
  • K.O. Kruchinin, S.T. Boogert, P. Karataev, L.J. Nevay
    Royal Holloway, University of London, Surrey, United Kingdom
  • A.S. Aryshev, M.V. Shevelev, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  • B. Bolzon
    The University of Liverpool, Liverpool, United Kingdom
  • B. Bolzon, T. Lefèvre, S. Mazzoni
    CERN, Geneva, Switzerland
  Transverse electron beam diagnostics is crucial for stable and reliable operation of the future electron-positron linear colliders such as CLIC or Higgs Factory. The-state-of-the-art in transverse beam diagnostics is based on the laser-wire technology. However, it requires a high power laser significantly increases the cost of the laser-wire system. Therefore, a simpler and relatively inexpensive method is required. A beam profile monitor based on Optical Transition Radiation (OTR) is very promising. The resolution of conventional OTR monitor is defined by a root-mean-square of the so-called Point Spread Function (PSF). In optical wavelength range the resolution is diffraction limited down to a few micrometers. However, in * we demonstrated that the OTR PSF has a structure which visibility can be used to monitor vertical beam size with sub-micrometer resolution. In this report we shall represent the recent experimental results of a micron-scale beam size measurement. We shall describe the entire method including calibration procedure, new analysis, and calculation of uncertainties. We shall discuss the hardware status and future plans.
* P. Karataev et al., Physical Review Letters 107, 174801 (2011).
slides icon Slides WEAL2 [5.120 MB]  
WEPC34 Time Trend Observation of Certain Remarked Bunches using a Streak Camera 761
  • T. Naito, S. Araki, H. Hayano, K. Kubo, S. Kuroda, T.M. Mitsuhashi, T. Okugi, S. Sakanaka, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  Funding: This work is supported by Japan-U.S. cooperative program .
A streak camera with two dimensional sweep function can measure the trend of the longitudinal beam profile in the ring. In the case of the multi-bunch measurement, the different bunch profile sit on same timing, thus, we can not distinguish the behavior of each bunch. We have developed a trigger circuit to measure the bunch-by-bunch longitudinal beam profile, which uses non integer sweep frequency for the acceleration frequency. The bunch profile of each bunch sit on different position in this measurement. We observed the increment of the synchrotron oscillation amplitude from the first bunch to the 20th bunch in the KEK-ATF Damping Ring by using this system. This paper describes the hardware and the measurement results.