Author: Gaudreau, M.P.J.
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WEPMF063 Thyratron Replacement* 2512
 
  • I. Roth, N. Butler, M.P.J. Gaudreau, M.K. Kempkes, R.E. Simpson
    Diversified Technologies, Inc., Bedford, Massachusetts, USA
 
  Funding: Funded under US DOE grant no. DE-SC0011292.
Thyratrons are typically used as the switch in high power, short pulse modulators with pulse-forming networks. However, thyratrons have a lifetime of only ten to twenty thousand hours, their reservoir heater voltage needs to be adjusted periodically, and reduced overall demand has led multiple thyratron vendors to slow or cease production. In contrast, solid-state switches have a much longer lifetime, need no maintenance, and are based on widely-available commercial items. Despite these advantages, solid-state devices have not historically seen use, due to limited voltage, current, and risetime. Diversified Technologies, Inc. (DTI) has removed this barrier, having developed, built, and tested a thyratron-replacement switch for SLAC based on an array of series and parallel-connected commercial insulated-gate bipolar transistors (IGBTs). This switch has demonstrated operation at very high voltage and current, meeting the full specifications required by SLAC to completely replace (form-fit-function-interface) the L-4888 thyratron: 48 kV, 6.3 kA, and 1 µs risetime.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF063  
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WEPMF064 Daresbury Laboratory Short Pulse Klystron Modulators 2515
 
  • C. Chipman, M.P.J. Gaudreau, L. Jashari, M.K. Kempkes, J. Kinross-Wright, R.E. Simpson
    Diversified Technologies, Inc., Bedford, Massachusetts, USA
  • S.A. Griffiths, A.E. Wheelhouse
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • H.J. Zhang
    Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People's Republic of China
 
  Diversified Technologies, Inc. (DTI) has developed a unique short pulse klystron modulator system for the Compact Linear Advanced Research Accelerator (CLARA) Project at Daresbury Laboratory. One unit has been delivered and three more are on contract. This system is based on the combination of a high voltage solid-state switch, with a conventional 1:7 pulse transformer, and a passive pulse corrector with automated adjustment. This unique passive circuitry delivers the extremely flat output pulse required for advanced accelerator applications. The CLARA modulators share design elements with previous DTI modulators which provides both a lower cost and easier to maintain system. The modulators are designed to pulse 80 MW-class klystrons at an avg power of 250 kW and provides adjustable high efficiency operation in the 45 kV to 450 kV range for currents up to 545 A and pulse lengths of 1.5 to 4.0 µs. One key objective of modulator development is optimization of voltage flatness (± 0.02 %), stability (± 0.05 %), and reproducibility (± 0.05 %).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF064  
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WEPMF065 High Efficiency, High Power, Resonant Cavity Amplifier For PIP-II 2518
 
  • M.P.J. Gaudreau, N. Butler, D.B. Cope, P. H. Gordon, E.G. Johnson, M.K. Kempkes, R.E. Simpson
    Diversified Technologies, Inc., Bedford, Massachusetts, USA
 
  Funding: Funded under US DOE grant no. DE-SC0015780
Diversified Technologies, Inc. (DTI) is developing an integrated resonant-cavity combined solid-state amplifier for the Proton Improvement Plan-II (PIP-II) at Fermilab. The prototype has demonstrated multiple-transistor combining at 71% efficiency, at 675 watts per transistor at 650 MHz. The design simplifies solid-state transmitters to create straightforward scaling to high power levels. A crucial innovation is the reliable "soft-failure" mode of operation; a failure in one or more of these myriad combined transistors has negligible performance impact. The 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. DTI's design increases the power level at which it is cost-effective to employ a solid-state transmitter. DTI is upgrading the system to accommodate more transistors in each cavity module, and then will design and build a complete 100 kW-class transmitter which will consist of four such cavity modules and a combiner.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF065  
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