Author: Crofford, M.T.
Paper Title Page
WEPPC106 The First ASME Code Stamped Cryomodule at SNS 2465
  • M.P. Howell, D.R. Bruce, M.T. Crofford, D.L. Douglas, S.-H. Kim, S.E. Stewart, W.H. Strong
    ORNL, Oak Ridge, Tennessee, USA
  • R. Afanador, B.S. Hannah, J. Saunders
    ORNL RAD, Oak Ridge, Tennessee, USA
  • J.D. Mammosser
    JLAB, Newport News, Virginia, USA
  The first spare cryomodule for the Spallation Neutron Source (SNS) has been designed, fabricated, and tested by SNS personnel. The approach to design for this cryomodule was to hold critical design features identical to the original design such as bayonet positions, coupler positions, cold mass assembly, and overall footprint. However, this is the first SNS cryomodule that meets the pressure requirements put forth in the 10 CFR 851: Worker Safety and Health Program. The most significant difference is that Section VIII of the ASME Boiler and Pressure Vessel Code was applied to the vacuum vessel of this cryomodule. Applying the pressure code to the helium vessels within the cryomodule was considered. However, it was determined to be schedule prohibitive because it required a code case for materials that are not currently covered by the code. Good engineering practice was applied to the internal components to verify the quality and integrity of the entire cryomodule. The design of the cryomodule, fabrication effort, and cryogenic test results will be reported in this paper.  
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.
WEPPC108 Status of SRF Facilities at SNS 2471
  • J. Saunders, R. Afanador, T. Xu
    ORNL RAD, Oak Ridge, Tennessee, USA
  • M.T. Crofford, M.P. Howell, S.-H. Kim, S.E. Stewart
    ORNL, Oak Ridge, Tennessee, USA
  SNS has recognized the need for developing in-house capability to ensure long term sustainability of the SCL. SNS has made substantial gains in the last 6 years in understanding SCL operation, including system and equipment limiting factors, and resolution of system and equipment issues. Significant effort and focus is required to assure ongoing success in the operation, maintenance, and improvement of the SCL and to address the requirements of the upgrade project for the Second Target Station. This interdependent effort includes implementation of demonstrated improvements, fabrication of spare cryomodules, cavity R&D to enhance machine performance, and related SRF facility developments. Cryomodule and vertical cavity testing facilities are being developed to demonstrate process capabilities and to further understand the collective limitations of installed cavities. The status and future plans for SRF facilities at SNS will be presented.