Author: Karataev, P.
Paper Title Page
MOPC34 Longitudinal Beam Profile Monitor for Investigating the Microbunching Instability at Diamond Light Source 143
 
  • W. Shields, R. Bartolini, A.F.D. Morgan, G. Rehm
    Diamond, Oxfordshire, United Kingdom
  • R. Bartolini, P. Karataev
    JAI, Egham, Surrey, United Kingdom
  • P. Karataev
    Royal Holloway, University of London, Surrey, United Kingdom
 
  An investigation into the microbunching instability at Diamond Light Source has recently been conducted. Beyond the instability threshold, the bunch emits bursts of coherent synchrotron radiation with wavelengths comparable to the bunch length or shorter. The operating conditions for producing the instability include both normal optics, and low-alpha optics, where the bunch length can be shortened to a few picoseconds. A Michelson interferometer has been designed and installed utilising a silicon crystal wafer beamsplitter. Large bandwidth, room temperature pyroelectric detectors and low-noise, fast-response Schottky Barrier diode detectors have been employed to generate interferograms. In this paper, we describe the observed spectral content and the resulting calculated bunch length.  
 
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]  
 
WEPF18 Zemax Simulations of Diffraction and Transition Radiation 852
 
  • T. Aumeyr, P. Karataev
    JAI, Egham, Surrey, United Kingdom
  • M.G. Billing
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • L.M. Bobb, B. Bolzon, T. Lefèvre, S. Mazzoni
    CERN, Geneva, Switzerland
 
  Diffraction Radiation (DR) and Transition Radiation (TR) are produced when a relativistic charged particle moves in the vicinity of a medium or through a medium respectively. The target atoms are polarised by the electric field of the charged particle, which then oscillate thus emitting radiation with a very broad spectrum. The spatial-spectral properties of DR/TR are sensitive to various electron beam parameters. Several projects aim to measure the transverse (vertical) beam size using DR or TR. This paper reports on how numerical simulations using Zemax can be used to study such a system.  
poster icon Poster WEPF18 [0.573 MB]  
 
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]  
 
WEAL3 Diffraction Radiation Test at CesrTA for Non-Intercepting Micron-Scale Beam Size Measurement 619
 
  • L.M. Bobb, E. Bravin, T. Lefèvre, S. Mazzoni
    CERN, Geneva, Switzerland
  • T. Aumeyr, P. Karataev
    Royal Holloway, University of London, Surrey, United Kingdom
  • M.G. Billing, J.V. Conway
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • L.M. Bobb
    JAI, Egham, Surrey, United Kingdom
 
  Diffraction radiation (DR) is produced when a relativistic charged particle moves in the vicinity of a medium. The electric field of the charged particle polarizes the target atoms which then oscillate, emitting radiation with a very broad spectrum. The spatial-spectral properties of DR are sensitive to a range of electron beam parameters. Furthermore, the energy loss due to DR is so small that the electron beam parameters are unchanged. DR can therefore be used to develop non-invasive diagnostic tools. To achieve the micron-scale resolution required to measure the transverse (vertical) beam size using incoherent DR in CLIC, DR in UV and X-ray spectral-range must be investigated. Experimental validation of such a scheme is ongoing at CesrTA at Cornell University, USA. Here we report on the test using 0.5 mm and 1 mm target apertures on a 2.1 GeV electron beam and 400 nm wavelength.  
slides icon Slides WEAL3 [2.893 MB]  
 
WEPF36 X-ray Cherenkov Radiation as a Source for Relativistic Charged Particle Beam Diagnostics 910
 
  • A.S. Konkov, A.S. Gogolev, A. Potylitsyn
    TPU, Tomsk, Russia
  • P. Karataev
    Royal Holloway, University of London, Surrey, United Kingdom
 
  Funding: The work was partially supported by Russian Ministry of Science and Education within the grant No. 14.B37.21.0912.
Recent progress in development of accelerator technology for future linear colliders and X-ray free electron lasers has generated an interest in developing novel diagnostics equipment with resolution surpassing the unique beam parameters. Cherenkov radiation (CR) in the X-ray region in the vicinity of the absorption edges is one of the promising sources for relativistic charged particle beam diagnostics. In this work we have demonstrated CR characteristics in the X-ray region significantly depend on the energy of the emitted photons, because the CR is only generated in the frequency region in the vicinity of the atomic absorption edges, where the well-known Cherenkov condition is work. This peculiarity can be explained by resonance behaviour of the permittivity in the frequency range. It will result in the fact that the CR will stand out of any other types of polarisation radiation both on intensity and shape of angular distribution giving a unique opportunity to apply this phenomenon for charged particle beam diagnostics.
 
poster icon Poster WEPF36 [42.675 MB]