A high-voltage hard-switch modulator for the international linear collider

Diversified Technologies, Inc. (DTI) is developing a solid-state hard-switch modulator for the International Linear Collider, under the U.S. DOE SBIR program. This modulator will supply pulses at up to 135 kV, 165 A, and 1.5 ms for the 1.3-GHz klystrons. The full voltage is switched, so no transformer is needed. To achieve the required pulse flatness (plusmn0.5% at 5 Hz) without a large capacitor bank, an LC bouncer compensates for the voltage droop. The main capacitor, which stores 92 kJ, is charged by a 185-kW DTI inverter driving a four-stage voltage multiplier. The bouncer capacitor is charged by a commercial high-voltage supply. The main and bouncer switches are housed in an oil-filled tank, along with the inverter transformer, multiplier, bouncer inductor, and bouncer capacitor. The main capacitor bank is housed in a separate tank. This paper describes possible modulator architectures, the design of the selected LC-bouncer, and initial testing results.