Thyratrons, ignitrons, and spark gaps are used to switch tens of kilovolts at high current and at high rate of current risetime in high power modulators for high energy particle accelerators and other applications. These devices have one or more disadvantages, including high cost, limited lifetime, large expense for maintenance and/or replacement, and complexity of mounting, cooling and triggering. This project will develop a modular switch design that uses thyristors capable of high di/dt without saturable inductors; uses a portion of the energy that is being switched to drive the gates, simplifying isolation and triggering; is easy to mount and cool; and will result in an economical switch. In Phase I, an experimental switch module was developed and tested. It was shown that a 10 kV module can operate reliably at >8kA, at di/dts >30 kA/µs, for a 3 µs pulse. Operation of 3 modules in series at 30 kV with similar current pulses showing simultaneous turn-on and good voltage sharing between modules was demonstrated. In Phase II, a prototype 10 kV module will be developed and tested at high power with emphasis on thermal design and packaging to maximize its power handling capability while minimizing thermal fatigue. This module will be used as the basis of a compact 50kV prototype switch that will be developed, tested and delivered to the Department of Energy. This switch can be used to replace thyratrons in existing systems.
Commercial Applications and Other Benefits as described by the awardee: Systems that should benefit from these switches include pulse modulators for high power RF and microwave amplifiers used in particle accelerators, radar, and defense applications; industrial medium and high power pulsed lasers; kicker magnet drives; compact medical and industrial x-ray sources; pulsed electron, ion, or radiation sources for material processing, and food and water purification.
