Author: Geng, X.
Paper Title Page
WEPPC107 RF Distribution System for High Power Test of the SNS Cryomodule 2468
  • S.W. Lee, M. Broyles, M.T. Crofford, X. Geng, Y.W. Kang, S.-H. Kim, R.C. Peglow, C.L. Phibbs, W.H. Strong, A.V. Vassioutchenko
    ORNL, Oak Ridge, Tennessee, USA
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
A four-way waveguide RF power distribution system for testing the SNS multi-cavity cryomodule to investigate the collective behavior has been developed. A single klystron operating at 805MHz in 60Hz 8% duty cycle powers the 4-way waveguide splitter to deliver up to 600 kW to Individual cavities. Each cavity is fed through a waveguide vector modulator at each splitter output with magnitude and phase control. Waveguide vector modulator consists of two quadrature hybrids and two motorized waveguide phase shifters. The phase shifters and the assembled waveguide vector modulators were individually tested and characterized for low power and high pulsed RF power in the SNS RF test facility. Precise calibrations of magnitude and phase are done to generate the look up tables (LUTs) to provide operation references during the cryomodule test. An IQ demodulator board was developed and utilized to generate 2-port magnitude and phase LUTs. PLC units were developed for mechanical control of the phase shifters. Labview software was programmed for the measurements and the system operation. LUT based operation algorithm was implemented into EPICS control for the cryomodule test stand.