Comparative life testing of conventional trigatron type spark gaps and low pressure hollow electrode switches in a high energy (500 J) test circuit

A program of development has been undertaken at EEV to optimise the performance of low pressure hollow electrode switches in a high energy capacitor discharge application. A hollow electrode switch is a device which operates in the low pressure regime to the left of the Paschen minimum using a cold cathode. Triggering is initiated in the area behind the cathode, remote from the area in which the main current switching takes place. It is this fact which enables considerable lifetime benefits to be obtained over conventional trigatron type spark gaps, which typically come to the end of their life due to damage to the trigger electrode, situated in the area of main current switching. This paper reports the results of lifetime measurements in a high energy test circuit for both hollow electrode switches and comparable trigatron type spark gaps