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Wilson, J. L.

Paper Title Page
WEPMS075 Development and Testing of High Power RF Vector Modulators 2508
  • Y. W. Kang, M. S. Champion, T. W. Hardek, S.-H. Kim, M. P. McCarthy, A. V. Vassioutchenko, J. L. Wilson
    ORNL, Oak Ridge, Tennessee
  Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U. S. Department of Energy.

High power vector modulators can allow a fan-out RF power distribution system that can power many accelerating cavities from a single high-power klystron amplifier. The configuration enables independent control of amplitudes and phases of RF voltages at the cavities. A vector modulator employs either one or two hybrids with two fast phase shifters. Prototype high power RF vector modulators employing a hybrid and two fast ferrite phase shifters in coaxial TEM transmission lines for 402.5 MHz and 805 MHz are built and tested. RF properties of the design and result of high power testing are presented.

WEPMS080 SRF Cavity Transient Beam Loading Detection - Simulation and Measurement 2517
  • Y. Zhang, I. E. Campisi, C. Deibele, J. Galambos, S. Henderson, Y. W. Kang, H. Ma, J. L. Wilson
    ORNL, Oak Ridge, Tennessee
  Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U. S. Department of Energy.

Beam phase measurement based on detection of transient beam loading signal in a Superconducting (SC) cavity is utilized to setup the cavity synchronous phase. It has the potential to become a fast tune-up technique for a high intensity SC electron linac, as cavity phase could be determined precisely with only a few beam pulses. The paper introduces a transient detector study in the Spallation Neutron Source (SNS) proton linac, and discusses one of the major challenges - stochastic noise in the cavity RF system, which deteriorates the precision and increases the time needed for phase measurement with this technique. We analyze the influence of RF noise to the phase measurement in a simulation study with a beam-cavity model. Beam signal measurement with the cavity Low Level RF (LLRF) system and the initial experiment of prototype detectors are briefly introduced.