Author: Aryshev, A.S.
Paper Title Page
MOPF04 Results of the High Resolution OTR Measurements at KEK and Comparison with Simulations 204
 
  • B. Bolzon, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A.S. Aryshev
    KEK, Ibaraki, Japan
  • B. Bolzon, T. Lefèvre, S. Mazzoni
    CERN, Geneva, Switzerland
  • B. Bolzon, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • P. Karataev, K.O. Kruchinin
    Royal Holloway, University of London, Surrey, United Kingdom
  • P. Karataev
    JAI, Egham, Surrey, United Kingdom
 
  Optical Transition Radiation (OTR) is emitted when a charged particle crosses the interface between two media with different dielectric properties. It has become a standard tool for beam imaging and transverse beam size measurements. At the KEK Accelerator Test Facility 2 (ATF2), OTR is used at the beginning of the final focus system to measure a micrometre beam size using the decrease in visibility of the OTR Point Spread Function (PSF). In order to study and improve the resolution of the optical system, a novel simulation tool has been developed in order to characterize the PSF in detail. Based on the physical optic propagation mode of ZEMAX, the propagation of the OTR electric field can be simulated very precisely up to the image plane, taking into account aberrations and diffraction coming through the designed optical system. This contribution will show the results of measurements performed after a first improvement of the ATF2 OTR optical design to confirm the very high resolution of the imaging system and the performance of this simulation tool.  
poster icon Poster MOPF04 [1.590 MB]  
 
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.  
 
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]