Author: Bartolini, R.
Paper Title Page
MOPPP069 First Measurements of COLDDIAG: A Cold Vacuum Chamber for Diagnostics 720
  • S. Gerstl, T. Baumbach, S. Casalbuoni, A.W. Grau, M. Hagelstein, T. Holubek, D. Saez de Jauregui
    Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
  • R. Bartolini, M.P. Cox, J.C. Schouten, R.P. Walker
    Diamond, Oxfordshire, United Kingdom
  • M. Migliorati, B. Spataro
    INFN/LNF, Frascati (Roma), Italy
  • I.R.R. Shinton
    UMAN, Manchester, United Kingdom
  Superconductive insertion devices can reach, for the same gap and period length, higher fields with respect to permanent magnet insertion devices. One of the still open issues for the development of superconductive insertion devices, is the understanding of the heat intake from the electron beam. COLDDIAG, a cold vacuum chamber for diagnostics was designed and built specifically for this purpose. With the equipped instrumentation, which covers temperature sensors, pressure gauges, mass spectrometers as well as retarding field analyzers it is possible to measure the beam heat load, total pressure, gas content as well as the flux of particles hitting the chamber walls. Here we report about the preliminary measurements and results of COLDDIAG installed in the Diamond storage ring.  
TUPPP028 A Study of Girder Alignment with Survey Measurements In the Diamond Storage Ring 1674
  • M. Apollonio, R. Bartolini, R.T. Fielder, W.J. Hoffman, J. Kay, I.P.S. Martin, B. Singh
    Diamond, Oxfordshire, United Kingdom
  Using a model of the Diamond storage ring which includes displacements and rotations of the 74 magnet girders an attempt has been made to correlate survey data with the corrector magnet (CM) strengths required for a zero orbit. We then use the model to deduce the most effective girder movements that will bring about a reduction in corrector strength. We describe the results of these studies, and suggest a test with a deliberately displaced girder and the effect on corrector strengths, aimed at enhancing our understanding of the system  
WEPPR079 Observations of Microbunching Instabilities from a THz Port at Diamond Light Source 3114
  • W. Shields, G.E. Boorman, V. Karataev, A. Lyapin
    JAI, Egham, Surrey, United Kingdom
  • R. Bartolini, A.F.D. Morgan, G. Rehm
    Diamond, Oxfordshire, United Kingdom
  Diamond Light source is a third generation synchrotron facility dedicated to producing radiation of outstanding brightness. Above a threshold current, the electron bunches are susceptible to the phenomenon known as the microbunching instability. This instability is characterised by the onset of radiation bursts, the wavelength of which is around one order of magnitude shorter than the bunch length. Near threshold, the bursting occurs quasi-­‐periodically, however at higher currents, the bursting appears randomly. The high frequencies involved in these emissions make detection and analysis challenging. A port specifically for the investigation of mm wave emissions has recently been built at Diamond. Ultra fast Schottky Barrier Diode detectors have been installed to obtain data for only a small fraction of the bunch revolution time in an updated data acquisition system. The threshold current and subsequent evolution of the instability have been investigated.  
TUPPP031 Modelling the Steady-state CSR Emission in Low Alpha Mode at the Diamond Storage Ring 1677
  • I.P.S. Martin, C.A. Thomas
    Diamond, Oxfordshire, United Kingdom
  • R. Bartolini
    JAI, Oxford, United Kingdom
  The CSR emitted by short electron bunches can be of a stable or bursting nature, with transition between the two states characterised by a threshold current that depends on various machine parameters. Key to understanding this process is to develop an effective model that describes the way the electron bunch interacts with impedance sources such as the CSR wakefield and surrounding vacuum chamber. In this paper we present the latest results of modelling the equilibrium distribution calculated using the Haissinski equation driven by different impedance models. The bunch lengthening with current, bunch profiles and CSR form factors derived from this model are compared to measured data for both positive and negative momentum compaction factor. Comparisons of the measured bursting thresholds to theoretical predictions are also discussed.  
TUPPP066 CLARA - A Proposed New FEL Test Facility for the UK 1750
  • J.A. Clarke, D. Angal-Kalinin, D.J. Dunning, S.P. Jamison, J.K. Jones, J.W. McKenzie, B.L. Militsyn, N. Thompson, P.H. Williams
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • R. Bartolini
    JAI, Oxford, United Kingdom
  • I.P.S. Martin
    Diamond, Oxfordshire, United Kingdom
  A new single pass national FEL test facility, CLARA, is proposed to be constructed at Daresbury Laboratory in the UK. The aim of CLARA is to develop a normal conducting test accelerator able to generate longitudinally and transversely bright electron bunches and to use these bunches in the experimental production of stable, synchronized, ultra short photon pulses of coherent light from a single pass FEL with techniques directly applicable to the future generation of light source facilities. In addition the facility will be an ideal test bed for demonstrating innovative technologies such as high repetition rate normal conducting RF linacs and advanced undulator designs. This paper will describe the design of CLARA, pointing out the flexible features that will be incorporated to allow multiple novel FEL schemes to be proven.