Our high power modulators and power supplies are used world wide in demanding research applications in the Department of Energy's national laboratories and leading research universities.

Argonne Laboratory Opening Switch - Early in 2003, DTI delivered a solid-state, 95 kV, 21 A opening series switch for the Advanced Light Source at Argonne National Laboratory. The switch replaces a mercury ignitron crowbar and is placed in series with the klystron cathode, opening when an arc is detected. Its operating time, including arc detection and switch opening, is under 700 ns, much faster than any known crowbar. The high voltage can be turned back on as soon as the arc clears, allowing beam operation to continue through a klystron arc.

The system includes a high speed, linear solid-state voltage regulator for controlling the klystron cathode - mod-anode voltage from the existing unregulated cathode supply, as well as filament supplies, and controls for the full range of klystron operation. Plans call for replacement of all five of the environmentally-hazardous mercury ignitrons in the system with solid state switches, and upgrades to the DC cathode power supplies. This fully solid state design is applicable to any pulsed or CW accelerator klystron.

Hybrid Modulator - Under a recently completed Phase II SBIR program, DTI delivered a "hybrid" modulator to Stanford Linear Accelerator Center for the Next Linear Collider, in Oct 2002. The solid-state switch operates at 80 kV, 530 A and drives a 6.5:1 pulse transformer to 500 kV/500 A for 3µs. It has been tested at full pulse power at DTI, fully meeting the NLC requirements. During 2003, the modulator will be evaluated at full power with the NLC klystrons at SLAC.

High Power Conditioning - Conditioning and test of high power microwave tubes, such as klystrons and gyrotrons, is a complex process because tubes must be conditioned over increasing voltages and input power levels to achieve reliable performance without damage. Careful control of voltage, pulsewidth, and PRF, at very high power (20 MW +) and voltage (100 kV +) is required for success. The cost of conditioning is also an important factor in the development, production, and operation of high power microwave tubes. Conventional modulator technologies capable of switching these high power levels are limited in their flexibility, and require significant operator knowledge and time to reach full performance.

DTI built a 140 kV, 500 A peak solid state modulator to operate at pulsewidths from 1 microsecond to DC, and at PRFs of more than 10 kHz. Two high power switches in a unique modulator/buck regulator configuration were combined to provide the required efficiency and control. The complete 70 MW peak power switch measured approximately 48" x 36" x 18", and is packaged with storage capacitor, control circuitry, and voltage and current monitors in a complete modulator system. The configuration was installed in a leading tube manufacturer's MSR test set.

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Argonne Opening Switch

Hybrid Modulator