Author: Bartolini, R.
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.  
TUPC11 Beam-Based Measurement of ID Taper Impedance at Diamond 380
  • V.V. Smaluk, R. Bartolini, R.T. Fielder, G. Rehm
    Diamond, Oxfordshire, United Kingdom
  New insertion devices (IDs) are being designed now for a Diamond upgrade. One of the important topics of the design is the coupling impedance of the ID vacuum chamber movable tapers. To get a complete and reliable information of the impedance, analytical estimations, numerical simulation and beam-based measurement have been performed. The impedance of an existing ID taper geometrically similar to the new one has been measured using the orbit bump method. It turns out that in spite of the small magnitude (a few um) of orbit distortion to be observed in this case, the BPM resolution is sufficient for this measurement. The measurement results in comparison with simulation data are discussed in this paper.  
TUPC38 Longitudinal Profile Monitor Using Smith-Purcell Radiation: Recent Results from the E-203 Collaboration 464
  • N. Delerue, J. Barros, S. Le Corre, M. Vieille Grosjean
    LAL, Orsay, France
  • H.L. Andrews
    LANL, Los Alamos, New Mexico, USA
  • F. Bakkali Taheri, R. Bartolini, G. Doucas, I.V. Konoplev, C. Perry, A. Reichold, S. Stevenson
    JAI, Oxford, United Kingdom
  • V. Bharadwaj, C.I. Clarke
    SLAC, Menlo Park, California, USA
  • N. Fuster Martinez
    IFIC, Valencia, Spain
  • M. Labat
    SOLEIL, Gif-sur-Yvette, France
  Funding: Financial support from the John Adams Institute, the Fell Fund (University of Oxford), the Université Paris-Sud (programme 'Attractivité') and the French ANR (contract ANR-12-JS05-0003-01).
We report on recent measurements made at FACET by the E-203 collaboration to test a longitudinal bunch profile monitor based on Coherent Smith-Purcell radiation. The capacity of this monitor to resolve sub-picosecond bunches will be shown as well as a comparison of profile reconstructed for different beam compression settings. We will also present recent electromagnetic simulations of the interactions between the beam and the grating as well as the expected resolution of such monitor. Comparison between Coherent Smith-Purcell radiation measurement and those made with other techniques will also be discussed. Finally future upgrades of the experiment and steps toward the construction of a single shot longitudinal profile monitor will be presented.