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Bolme, G. O.

Paper Title Page
WEPMS021 RF-loss Measurements in an Open Coaxial Resonator for Characterization of Copper Plating 2376
 
  • F. L. Krawczyk, G. O. Bolme, W. L. Clark, J. P. Kelley, F. A. Martinez, D. C. Nguyen, K. A. Young
    LANL, Los Alamos, New Mexico
  • J. Rathke, D. L. Schrage, T. Schultheiss, L. M. Young
    AES, Medford, NY
 
  Funding: Work supported by the Office of Naval Research and the High-Energy Laser Joint Technology Office.

An experiment has been conducted to measure small differences in cavity Q caused by various cavity surface treatments. A requirement of the experiment was that it show little sensitivity to the reassembly with various test pieces. We chose a coaxial half-wave resonator, with an outer conductor extending significantly beyond the length of the inner conductor. The outer conductor acts as a cut-off tube, eliminating the need for electric termination and thus any RF-contacts that can influence the Q-measurements. The experiment is aimed at qualifying the performance of cyanide-copper plated GlidCop in comparison with that of a machined GlidCop surface. To maximize the sensitivity of the measurement we use a fixed outer conductor made of annealed OFE copper and only replace the inner conductor, which is mounted on a low-loss Teflon pedestal located in the low electric field region. The Q-values of machined GlidCop and cyanide-copper plated GlidCop inner conductors are measured against the reference Q of the annealed OFE co-axial cavity. This simple configuration allows a statistically significant number of repetitions of measurements and should provide accurate comparative measurements.

 
WEPMS029 LANSCE RF System Refurbishment 2400
 
  • D. Rees, G. O. Bolme, J. T. Bradley III, S. Kwon, J. T.M. Lyles, M. T. Lynch, M. S. Prokop, W. Reass, K. A. Young
    LANL, Los Alamos, New Mexico
 
  The Los Alamos Neutron Science Center (LANSCE) is in the planning phase of a refurbishment project that will sustain reliable facility operations well into the next decade. The LANSCE accelerator was constructed in the late 1960s and early 1970s and is a national user facility that provides pulsed protons and spallation neutrons for defense and civilian research and applications. The refurbishment will focus on systems that are approaching 'end of life' and systems where modern upgrades hold the promise for significant operating cost savings. The current baseline consists of replacing all the 201 MHz RF systems, upgrading a substantial fraction of the 805 MHz RF systems to high efficiency klystrons, replacing the high voltage systems, and replacing the low level RF cavity field control systems. System designs will be presented. The performance improvements will be described and the preliminary cost and schedule estimates will be discussed.  
WEPMS033 LANSCE 201 MHz and 805 MHz RF System Experience 2412
 
  • K. A. Young, G. O. Bolme, J. T.M. Lyles, M. T. Lynch, E. P. Partridge, D. Rees
    LANL, Los Alamos, New Mexico
 
  Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396

The LANSCE RF system consists of four RF stations at 201 MHz and 44 klystrons at 805 MHz. In the LANSCE accelerator, the beam source is injected into the RF system at 0.75 MeV. The beam is then accelerated to 100 MeV in four drift tube linac (DTL) tanks, driven at 201.25 MHz. Each 201 MHz RF system consists of a train of amplifiers, including a solid state amplifier, a tetrode, and then at triode. After the DTL, the beam is accelerated from 100 MeV to 800 MeV in the forty-four coupled cavity linac (CCL) tanks at 805 MHz. The machine operates with a normal RF pulse width of 835 microseconds at a repetition rate up to 120 Hz, and sometimes operates with a pulse width up to 1.2 microseconds for single pulses. This RF system has been operating for about 37 years. This paper summarizes the recent operational experience. The reliability of the 805 MHz and 201 MHz RF systems is discussed, and a summary the lifetime data of the 805 MHz klystrons and 201 MHz triodes is presented.