• M.T. Crofford, T.W. Hardek, S.W. Lee, M.F. Piller
  ORNL, Oak Ridge, Tennessee
• J.A. Ball, T.L. Davidson
  ORNL RAD, Oak Ridge, Tennessee

The Spallation Neutron Source (SNS) has been operating since the first neutrons were produced on April 29, 2006. During the last several years the beam energy has been methodically ramped-up and outlying issues solved to improve system reliability. During the beam studies a temperature dependence has been discovered with the Low-Level RF systems. The effect is small but readily observable as increased beam losses. The temperature dependence has been studied both in the accelerator and in the laboratory and the sensitive components identified. A prototype solution that replaces the temperature dependent components of the Low-Level RF System has been designed and is in initial testing. Preliminary results of the laboratory tests have been encouraging. Accelerator tests are planned after installation during the December 2010 maintenance cycle.

• S.W. Lee, J.A. Ball, T.L. Davidson, S.L. Jones
  ORNL RAD, Oak Ridge, Tennessee
• M.T. Crofford, T.W. Hardek
  ORNL, Oak Ridge, Tennessee

The Spallation Neutron Source (SNS) High-Power Protection Module (HPM) provided interlocks and fast shutdown for the RF system to protect the accelerating structures and high power RF (HPRF) Distribution System. The HPM has required some functionality upgrades since the start of beam operations and an upgrade to the HPM test stand was required to support these added features. The HPM test stand currently verifies functionality, RF channel calibration, and measurement of the speed of shutdown to ensure the specifications are meet. The upgraded test stand was implemented in a single FPGA to allow for future growth and flexibility. Work is currently progressing on automation of the test stand to better perform the required module calibration schedule.