The development and testing of subnanosecond-rise, kilohertz oil switches for the generation of high-frequency impulses

An experimental program undertaken to demonstrate a switch technology capable of generating picosecond-risetime, multimegawatt pulses is reported. The goal was to identify and demonstrate a technology which could be scaled to hundreds of kilovolts as well as operate at kilohertz repetition rates. A picosecond-risetime, long-lifetime switch was also required. Spark gap technology capable of being scaled to much higher repetition rates and energy switching regimes, in particular, a flowing oil gap switch, was investigated. A two to three-pulse breakdown test at 130 kV was used to measure the recovery characteristics of a large-area oil switch at up to 200 pps. A high-repetition-rate modulator based on flowed oil switches that develop pulses tens of nanoseconds in duration was developed. The modulator incorporates three oil switches: (1) a transfer switch, (2) an output switch, and (3) a sharpening switch. The modulator design and performance are reported. The influence of electrode flow geometry on the recovery of oil switches along with their breakdown and other characteristics is described