Author: Lewandowski, J.R.
Paper Title Page
WEOBB201 Commissioning of the X-band Transverse Deflector for Femtosecond Electron/X-Ray pulse Length Measurements at LCLS 2091
  • Y.T. Ding, C. Behrens, J.C. Frisch, Z. Huang, P. Krejcik, J.R. Lewandowski, H. Loos, J.W. Wang, M.-H. Wang, J.J. Welch
    SLAC, Menlo Park, California, USA
  • C. Behrens
    DESY, Hamburg, Germany
  X-ray free-electron lasers provide ultrashort x-ray pulses from several to a few hundred femtoseconds for multidisciplinary users. However, tremendous challenges remain in the measurement and control of these ultrashort pulses with femtosecond precision, for both the electron beam and the x-ray pulses. A new diagnostic scheme adding a transverse radio-frequency deflector at the end of the linac coherent light source (LCLS) undulator beamline has been proposed*. Two 1-m long deflecting structures have been installed at LCLS during the summer of 2012. Installation of the high power RF components including the klystron, waveguide, RF controls etc. is proceeding and commissioning is scheduled for March 2013. We report the latest progress of the commissioning of the deflector at LCLS.
* Y. Ding et al., Phys. Rev. ST Accel. Beams 14, 120701 (2011)
slides icon Slides WEOBB201 [4.199 MB]  
WEPFI086 Normal Conducting Radio Frequency X-band Deflecting Cavity Fabrication, Validation and Tuning 2899
  • R.B. Agustsson, L. Faillace, A.Y. Murokh, E. Spranza, S. Storms
    RadiaBeam, Santa Monica, USA
  • D. Alesini
    INFN/LNF, Frascati (Roma), Italy
  • V.A. Dolgashev, J.R. Lewandowski
    SLAC, Menlo Park, California, USA
  • J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • V. Yakimenko
    BNL, Upton, Long Island, New York, USA
  An X-band Traveling wave Deflector mode cavity (XTD) has been developed, fabricated, tuned and characterized by Radiabeam Technologies to perform longitudinal measurement of the sub-picosecond ultra-relativistic electron beams. The device is optimized for the 100 MeV electron beam parameters at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory, and is scalable to higher energies. The XTD is designed to operate at 11.424 GHz, and features short filling time, femtosecond resolution, and a small footprint. RF design, structure fabrication, cold testing and tuning results are presented.  
WEPFI090 An X-band Dielectric-based Wakefield Power Extractor 2908
  • C.-J. Jing, S.P. Antipov, A. Kanareykin, P. Schoessow
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • M.E. Conde, W. Gai, J.G. Power
    ANL, Argonne, USA
  • V.A. Dolgashev, J.R. Lewandowski, S.G. Tantawi, S.P. Weathersby
    SLAC, Menlo Park, California, USA
  • I. Syratchev
    CERN, Geneva, Switzerland
  Funding: US DoE SBIR Phase II project under Contract#DE-SC0004322
An X-band dielectric-based wakefield power extractor is under development to function as a high power rf source primarily for Two Beam Accelerator applications. A low surface electric field to gradient ratio and low fabrication cost are two main advantages of the dielectric-loaded accelerating/decelerating structure. We have designed a 12 GHz dielectric-based power extractor that has similar performance parameters to the CLIC PETS (23 mm beam channel, 240 ns pulse duration, 135 MW output per structure) using the CLIC drive beam. In order to study potential rf breakdown issues, as a first step we built a 11.424 GHz dielectric-based power extractor scaled from the 12 GHz design. A high power rf test will be conducted using the SLAC 11.424 GHz high power rf source in Dec. 2012. Results of the high power testing will be reported. Meanwhile, the 12 GHz fully featured dielectric power extractor is also under construction; construction progress and bench tests will be discussed.
WEPME062 Short-Pulse Ti:Sapphire Laser System for Photocathode Research at SLAC 3076
  • W.J. Corbett, A. Brachmann, R.N. Coffee, A.R. Fry, S. Gilevich, N. Hartmann, W. Helml, P. Hering, E.N. Jongewaard, D. Kelley, J.R. Lewandowski, W. Polzin, J. Sheppard, P. Stefan, T. Vecchione, S.P. Weathersby, W.E. White, M. Woods, F. Zhou
    SLAC, Menlo Park, California, USA
  A photo-cathode research laboratory has been constructed at SLAC to test and characterize the spare LCLS electron gun. At the heart of the laboratory is a dual-purpose Ti:Sapphire oscillator/regen laser that can deliver either a 2.5ps, 760nm beam to the photocathode gun or a 35fs, 800nm beam to prototype diagnostics for the LCLS. The objective of the photocathode research is to definitively identify ‘recipes’ for high-reliability cathode processing resulting in high quantum efficiency and low beam emittance. The LCLS diagnostics program is presently aimed at developing spectral-encoding systems for shot-by-shot pulse arrival time measurements at the 10fs level. In this paper we review the Ti:Sapphire laser system and report on status of the photocathode and diagnostics programs.