Precise Laser Initiated Closure of Multimegavolt Spark Gaps

Abstract

Single- and double-channel laser triggered switches in high pressure gas have been designed and operated in the voltage range from 1 to more than 3 MV. Jitter times of <1 to 3 nsec were observed in most cases. Gas pressures of 10.5 and 21 kg·cm−2 were used. The gases were either 100% nitrogen or various mixtures of N2, SF6, and Ar. Significant accomplishments were (1) the simultaneous firing of four stages of a Marx generator by an optically divided laser beam, (2) up to 40% reduction in the risetime observed in the output pulse from a multimegavolt dc generator when switched into a load through two simultaneously laser triggered channels, and (3) the design and operation of a laser triggered, dc charged switch at more than 3 MV with subnanosecond jitter.