Time-Delay Characteristics of Laser Triggered Multi-Stage Vacuum Switch

Based on the working principle of laser triggered multi-stage gas switch and previous work on multi-break vacuum switch, a laser triggered multi-stage vacuum switch (LTMVS) composed of laser triggered vacuum gap and multi-stage self-breakdown vacuum gaps is proposed in this paper. LTMVS shows highly developing potential to be the substitute for laser triggered multi-stage gas switches in pulse power facilities. And a simplified prototype of LTMVS is established with a detachable vacuum chamber and a short vacuum gap. Based on theoretical analysis about the tested closing process of test prototype, the working process of the prototype can be equally divided into two periods, the trigger of vacuum chamber and the self-breakdown of short vacuum gap; thus, the delay time of LTMVS contains of triggering delay time of laser triggered vacuum gap and the self-breakdown delay time of multi-stage vacuum gaps. And the time-delay characteristics of the prototype are studied separately with above two periods under various applied voltage. The test results prove that, the triggering delay time of vacuum chamber and the self-breakdown delay time of short vacuum gap are both affected by operating voltage; thus, favorable time-delay characteristics of LTMVS can be obtained by regulating the voltage distribution between triggered vacuum gap and self-breakdown vacuum gaps properly. And the delay time of LTMVS prototype can be controlled within 60ns based on the test results.