Optimization of a high-voltage trigatron switch

Abstract

Work has been carried out to optimize the operation of a high-voltage trigatron switch. It is demonstrated here that the trigatron can operate in two different modes depending on the route of the initial breakdown. This initial breakdown can occur either to the adjacent electrode or to the opposite electrode. It is shown here that, for a given switch, the mode of operation depends only on the ratio of trigger voltage to working voltage. The optimization was based upon the suggestion that the optimum operation of a trigatron would occur when the trigger pin breaks down simultaneously to both the adjacent and the opposite electrodes. This occurs for the trigger to working voltage ratio, which results in equal mean electric fields across the main gap and the trigger gap. The experiments were carried out with working voltages, Vg, between −1 and −2 MV and with trigger voltage to working voltage ratios of between −2% and −8%. It is shown that the minimum delay and jitter figures are indeed obtained with the trigger voltage closest to this optimum value, Vt*. For the switch used here, this corresponded to a ratio of Vt*/Vg=−3.4%. A single switch was operated for two hundred shots with a working voltage of −2 MV and the optimum trigger voltage and gave an average delay of 44 ns with an overall jitter of 4.4 ns.