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Cassel, R. L.

Paper Title Page
WEPMS028 Converter-Modulator Design and Operations for the ILC L-band Test Stand 2397
 
  • W. Reass
    LANL, Los Alamos, New Mexico
  • C. Adolphsen, T. G. Beukers, C. Burkhart, R. L. Cassel, M. N. Nguyen, G. C. Pappas, R. Swent, A. C. de Lira
    SLAC, Menlo Park, California
  • D. E. Anderson
    ORNL, Oak Ridge, Tennessee
 
  Funding: This work supported by Stanford Linear Accelerator Center, Oak Ridge National Laboratory, and the Department of Energy.

To facilitate a rapid response to the International Linear Collider (ILC) L-Band development program at SLAC, a spare converter-modulator was shipped from Los Alamos. This modulator was to be a spare for the Spallation Neutron Source (SNS) accelerator at ORNL. The ILC application requires a 33% higher peak output power (15 MW) and output current (130 Amp). This presents significant design challenges to modify the existing hardware and yet maintain switching parameters and thermal cycling within the semiconductor component ratings. To minimize IGBT commutation and free-wheeling diode currents, a different set of optimizations, as compared to the SNS design, were used to tune the resonant switching networks. Additional complexities arose as nanocrystalline cores with different performance characteristics (as compared to SNS), were used to fabricate the resonant "boost" transformers. This paper will describe the electrical design, system modifications, modeling efforts, and resulting electrical performance as implemented for the ILC L-band test stand.

 
WEPMS044 High Power Switch for the SMTF Modulator 2445
 
  • M. N. Nguyen, R. L. Cassel
    SLAC, Menlo Park, California
 
  Funding: Work supported by the Department of Energy under contract No. DE-AC03-76SF00515.

A compact, water cooled, high power switch for the Superconducting Module Test Facility (SMTF) long-pulse klystron modulator has been designed and implemented at the Fermi National Accelerator Laboratory (FNAL). This solid-state switch is composed of six series devices, each having a rating of 4.5 kV at 2000 Adc. Latest generation, press-pack IGBT modules are utilized to reduce the physical size and complexity of the switch assembly. The new switch and its associated controller provide a high degree of redundancy and fail-safe operation, which meets the modulator requirements. This paper describes the general switch assembly, IGBT protection and control schemes, and test results.

 
TUOBC02 A New Type High Voltage Fast Rise/Fall Time Solid State Marx Pulse Modulator 865
 
  • R. L. Cassel, S. Hitchcock
    Stangenes Industries, Palo Alto, California
 
  A new type of solid state Marx modulator developed by Stangenes Industries has the capability of producing high voltage pulses with fast rise and fall time at high repetition rates. In addition it has the ability to produce dynamically flexible output amplitude and pulse width. The pulse modulator was developed for the Fermi Labs Tevatron Electron Lens Tune Compensation System. It can produce a 14kV pulse with 200 nanosecond rise time and 600 nanosecond full pulse width at a 25 kilohertz repetition rate. It has no overshot or reverse voltage, making it ideal for beam bunch manipulation. It is designed to operate into a 200 pfd, 800 Ω load. This design permits all of the sources of power including the 1kV charging power supply to be connected at the grounded end of the pulser. A second generation pulser is under development to operate at above 50 kHz repetition rate with an arbitrary voltage waveform and faster rise/fall time. The pulser can accommodate load arcing and incorporates built in redundancy to insure high availability. The paper delineates the unique design of the modulator and its performance.  
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