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Nguyen, D.C.

Paper Title Page
TPPE045 Normal-Conducting High Current RF Photoinjector for High Power CW FEL 2866
  • S.S. Kurennoy, D.C. Nguyen, D.L. Schrage, R.L. Wood
    LANL, Los Alamos, New Mexico
  • V. Christina, J. Rathke, T. Schultheiss
    AES, Princeton, New Jersey
  • L.M. Young
    TechSource, Santa Fe, New Mexico
  An RF photoinjector capable of producing high average current with low emittance and energy spread is a key enabling technology for high power CW FEL. The design of a 2.5-cell, pi-mode, 700-MHz normal-conducting RF photoinjector cavity with magnetic emittance compensation is completed. With average gradients of 7, 7, and 5 MV/m in its three accelerating cells, the photoinjector will produce a 2.5-MeV electron beam with 3-nC charge per bunch and transverse rms emittance below 7 mm-mrad. Electromagnetic modeling has been used extensively to optimize ridge-loaded tapered waveguides and RF couplers, and led to a new, improved coupler iris design. The results, combined with a thermal and stress analysis, show that the challenging problem of cavity cooling can be successfully solved. Fabrication of a demo 100-mA (at 35 MHz bunch repetition rate) photoinjector is underway. The design is scalable to higher average currents by increasing the electron bunch repetition rate, and provides a path to a MW-class FEL. This paper presents the cavity design and details of RF coupler modeling.  
WPAT036 A 700 MHZ, 1 MW CW RF System for a FEL 100mA RF Photoinjector 2413
  • W. Roybal, D.C. Nguyen, W. Reass, D. Rees, P.J. Tallerico, P.A. Torrez
    LANL, Los Alamos, New Mexico
  Funding: U.S. Department of Energy.

This paper describes a 700 MHz, 1 Megawatt CW, high efficiency klystron RF system utilized for a Free Electron Laser (FEL) high-brightness electron photoinjector (PI). The E2V klystron is mod-anode tube that operates with a beam voltage of 95 kV. This tube, operating with a 65% efficiency, requires ~96 watts of input power to produce in excess of 1 MW of output power. This output drives the 3rd cell of a 2-cell, p-mode PI cavity through a pair of planar waveguide windows. Coupling is via a ridge-loaded tapered waveguide section and "dog-bone" iris. This paper will present the design of the RF, RF transport, coupling, and monitoring/protection systems that are required to support CW operations of the 100 mA cesiated, semi-porous SiC photoinjector.

WPAP033 State-of-the-Art Electron Guns and Injector Designs for Energy Recovery Linacs (ERL) 2292
  • A.M.M. Todd, A. Ambrosio, H. Bluem, V. Christina, M.D. Cole, M. Falletta, D. Holmes, E. Peterson, J. Rathke, T. Schultheiss, R. Wong
    AES, Medford, NY
  • I. Ben-Zvi, A. Burrill, R. Calaga, P. Cameron, X.Y. Chang, H. Hahn, D. Kayran, J. Kewisch, V. Litvinenko, G.T. McIntyre, T. Nicoletti, J. Rank, T. Rao, J. Scaduto, K.-C. Wu, A. Zaltsman, Y. Zhao
    BNL, Upton, Long Island, New York
  • S.V. Benson, E. Daly, D. Douglas, H.F.D. Dylla, L. W. Funk, C. Hernandez-Garcia, J. Hogan, P. Kneisel, J. Mammosser, G. Neil, H.L. Phillips, J.P. Preble, R.A. Rimmer, C.H. Rode, T. Siggins, T. Whitlach, M. Wiseman
    Jefferson Lab, Newport News, Virginia
  • I.E. Campisi
    ORNL, Oak Ridge, Tennessee
  • P. Colestock, J.P. Kelley, S.S. Kurennoy, D.C. Nguyen, W. Reass, D. Rees, S.J. Russell, D.L. Schrage, R.L. Wood
    LANL, Los Alamos, New Mexico
  • D. Janssen
    FZR, Dresden
  • J.W. Lewellen
    ANL, Argonne, Illinois
  • J.S. Sekutowicz
    DESY, Hamburg
  • L.M. Young
    TechSource, Santa Fe, New Mexico
  Funding: This work is supported by NAVSEA, NSWC Crane, the Office of Naval Research, the DOD Joint Technology Office and by the U.S. DOE.

A key technology issue of ERL devices for high-power free-electron laser (FEL) and 4th generation light sources is the demonstration of reliable, high-brightness, high-power injector operation. Ongoing programs that target up to 1 Ampere injector performance at emittance values consistent with the requirements of these applications are described. We consider that there are three possible approaches that could deliver the required performance. The first is a DC photocathode gun and superconducting RF (SRF) booster cryomodule. Such a 750 MHz device is being integrated and will be tested up to 100 mA at the Thomas Jefferson National Accelerator Facility beginning in 2007. The second approach is a high-current normal-conducting RF photoinjector. A 700 MHz gun will undergo thermal test in 2006 at the Los Alamos National Laboratory, which, if successful, when equipped with a suitable cathode, would be capable of 1 Ampere operation. The last option is an SRF gun. A half-cell 703 MHz SRF gun capable of delivering 1.0 Ampere will be tested to 0.5 Ampere at the Brookhaven National Laboratory in 2006. The fabrication status, schedule and projected performance for each of these state-of-the-art injector programs will be presented.