TU3A —  Invited Oral Presentations   (11-Sep-12   13:30—14:50)
Chair: G. Apollinari, Fermilab, Batavia, USA
Paper Title Page
Synchronization of Accelerator Sub-systems with Ultimate Precision  
  • H. Schlarb
    DESY, Hamburg, Germany
  Precise synchronization of accelerator sub-systems such as LLRF stations, gun or seeding lasers, is a pre-requisite for the successful operation of modern linear accelerators. The synchronization demand is often below 10 fs. Using examples like FLASH at DESY, the European XFEL, or different seeding proposals and studies, a general overview should be given.  
slides icon Slides TU3A01 [3.855 MB]  
Advances in Photonic and Metamaterial RF structures  
  • R. Seviour
    University of Huddersfield, Huddersfield, United Kingdom
  Interest in the use of novel electromagnetic media for particle acceleration and EM wave generation is growing. In part driven by the possibility to overcome limiting issues in conventional technologies, and offer novel ways in which to accelerate particles. Photonic media can confine a single EM frequency whilst forcing all other frequencies to propagate away, significantly reducing the long range wakefield of a structure. The novel dispersion curves of metamaterials define unique particle-wave interactions enabling compact inverse Cherenkov acceleration. In this presentation we examine the use of photonic media and metamaterials for RF generation and particle acceleration. We review the physical processes and defining length scales, energy exchange mechanisms, examining the advantages offered by these media and the issues that can arise from their use.  
slides icon Slides TU3A02 [28.697 MB]  
First Electron Beam Operation of the LANL NCRF Photoinjector  
  • N.A. Moody
    LANL, Los Alamos, New Mexico, USA
  The first ever photoelectron beam from LANL's cw normal-conducting radio-frequency (NCRF) injector has been observed. The NCRF injector at Los Alamos has produced its first continuous-wave photoelectron beam at energy up to 2 MeV and average current of a few mA. Accelerating gradients up to 10 MV/m at the cathode were confirmed with end-point x-ray energy measurements. The photoelectron beams were produced using both a continuous-wave blue laser diode and a cw modelocked green laser irradiating thin films of CsK2Sb photocathodes deposited on a copper substrate. Both photocurrent and dark current were measured via a calibrated wall-current monitor, sensitive to a few μA levels. Preparation of CsK2Sb photocathodes using chemical vapour deposition in an ultrahigh vacuum chamber and photocathode transfer to the NCRF injector will be described. We will also show the importance of the RF contact between the photocathode plug and the NCRF injector backplate for successful cw operation at high power.  
slides icon Slides TU3A03 [1.755 MB]  
Electron Beam Current-profile Shaping via Transverse-to-longitudinal Phase-space Exchange  
  • Y.-E. Sun
    Fermilab, Batavia, USA
  Tunable subpicosecond electron bunch trains are experimentally demonstrated at the A0 photoinjector at Fermilab. In this talk, we report our experiment on electron beam current-profile shaping using a transverse-to-longitudinal phase-space exchange technique. An initial beam consisting of a set of horizontally-separated beamlets passes through a beamline that exchanges the horizontal and longitudinal phase spaces, thus the beam is converted into a train of bunches temporally separated with tunable bunch duration and separation. By choosing proper initial horizontal density profiles, other types of beam current-profile shaping are possible, such as the preferred triangle-shape in wake field acceleration experiments.  
slides icon Slides TU3A04 [1.924 MB]