Author: Bobb, L.
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WEPB14 Recent Results on Non-invasive Beam Size Measurement Methods Based on Polarization Currents 464
  • S. Mazzoni, M. Bergamaschi, O.R. Jones, R. Kieffer, T. Lefèvre, F. Roncarolo
    CERN, Geneva, Switzerland
  • A. Aryshev, N. Terunuma
    KEK, Ibaraki, Japan
  • L.Y. Bartnik, M.G. Billing, J.V. Conway, M.J. Forster, Y.L.P. Fuentes, J.P. Shanks, S. Wang
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • V.V. Bleko, A.S. Konkov, A. Potylitsyn
    TPU, Tomsk, Russia
  • L. Bobb
    DLS, Oxfordshire, United Kingdom
  • P. Karataev, K. Lekomtsev
    JAI, Egham, Surrey, United Kingdom
  • P. Karataev
    Royal Holloway, University of London, Surrey, United Kingdom
  We present recent results on non-invasive beam profile measurement techniques based on Diffraction Radiation (DR) and Cherenkov Diffraction Radiation (ChDR). Both methods exploit the analysis of broadband electromagnetic radiation resulting from polarization currents produced in, or at the boundary of, a medium in close proximity of a charged particle beam. To increase the resolution of DR, measurements were performed in the UV range at a wavelength of 250 nm. With such configurations, sensitivity to the beam size of a 1.2 GeV electron beam below 10 um was observed at the Accelerator Test Facility (ATF) at KEK, Japan. In the case of the ChDR, a proof of principle study was carried out at the Cornell Electron Storage Ring (CESR) where beam profiles were measured in 2017 on a 5.3 GeV positron beam. At the time of writing an experiment to measure the resolution limit of ChDR has been launched at ATF where smaller beam sizes are available. We will present experimental results and discuss the application of such techniques for future accelerators.  
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WEPB18 Performance of a Reflective Microscope Objective in an X-ray Pinhole Camera 477
  • L. Bobb, G. Rehm
    DLS, Oxfordshire, United Kingdom
  X-ray pinhole cameras are used to measure the transverse beam profile of the electron beam in the storage ring from which the emittance is calculated. As improvements to the accelerator lattice reduce the beam emittance, e.g. with upgrades to fourth generation synchrotron light sources, likewise the beam size will be reduced such that micron and sub-micron scale resolution is required for beam size measurement. Therefore the spatial resolution of the pinhole camera imaging system must be improved accordingly. Here, the performance of a reflective microscope objective is compared to the high quality refractive lens which is currently in use to image the scintillator screen to the camera. The modulation transfer functions for each system have been assessed and will be discussed.  
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