Author: Kempkes, M.K.
Paper Title Page
WEPVA141 Ion Cyclotron Resonance Heating Transmitter Opening Switch Upgrade 3600
 
  • M.P.J. Gaudreau, M.K. Kempkes, J. Kinross-Wright, R.E. Simpson
    Diversified Technologies, Inc., Bedford, Massachusetts, USA
 
  Diversified Technologies Inc. (DTI) has installed a high-power solid-state opening switch upgrade package to replace the mercury ignitron crowbars in the Ion Cyclotron Resonance Heating (ICRH) Transmitters at MIT Plasma Fusion Science Center's (PFSC) Alcator C Mod, a Tokamak-type fusion experimental device. The speed of the series opening switch avoids the large fault currents on the transformer and power feed inherent with a crowbar. This improvement enables re-optimization of the Transformer/Rectifier (T/R) set, ultimately allowing increased power output and increased tetrode reliability. The ratings of the prior high voltage power supply are a compromise between high output power (lower impedance required from the T/R set) and crowbar reliability (higher impedance required from the power supply to limit fault current). DTI's opening switch upgrade safely allows the use of significantly reduced transformer impedance and lower droop, giving increased power as well as improved tube protection. DTI's opening switch kit can readily be adapted to any similar transmitters as an upgrade from a crowbar.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA141  
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THPIK117 High Efficiency High Power Resonant Cavity Amplifier for Accelerator Applications 4374
 
  • M.P.J. Gaudreau, D.B. Cope, E.G. Johnson, M.K. Kempkes, J. Kinross-Wright, R.E. Simpson
    Diversified Technologies, Inc., Bedford, Massachusetts, USA
 
  Funding: Work supported by US Department of Energy under contract DE-SC0015780
Diversified Technologies, Inc. (DTI) has designed and built a unique integrated resonant-cavity combined solid-state amplifier. The design radically simplifies solid-state transmitters to create favorable and straightforward scaling to high power levels. A crucial innovation is demonstration of an inherently reliable soft-failure mode of operation; a failure in one or several of these myriad combined transistors has negligible performance impact. In addition, this design couples the transistor drains directly to the cavity without first transforming to 50 Ohms, avoiding the otherwise-necessary multitude of circulators, cables, and connectors. A conventional amplifier has a complete set of electrical and cooling connections for every stage, resulting in many hundreds of connections for a high power transmitter'in some DTI designs, there are as few as four. This construction both reduces the cost and increases the power level at which it is cost-effective to employ a solid-state transmitter. The prototype has demonstrated multiple-transistor combining from 300 MHz to 1300 MHz, at powers up to 5 kW. This prototype is scalable to several hundred kW at these frequencies.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK117  
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