Study on the breakdown characteristics of UV illumination switch under microsecond pulse

UV illumination switch is often utilized for pulse sharpening in large pulsed power devices. A lot of work has been done for UV illumination switch under nanosecond pulse¹ while the switch under microsecond pulse may show different performance². The purpose of this study is to figure out the breakdown characteristics of UV illumination switch under microsecond pulse. To analyse the development of discharge channel, the switch with two spherical electrodes and a HV needle electrode inside was designed and ICCD with a minimum exposure time of 10 ns was used to capture images of the discharge. What´s more, a similar higher voltage level switch was designed in this study. HV electrode of the switch was replaceable with three different types: the flat-head, the spherical-head and the saw-toothed. Factors which may influence the switch performance, including arrangement of electrodes, distance of main gap, current-limiting resistance of pre-ionizing gap, rise time of the pulse and gas type were experimeuncertaintyntally studied. Jitter of discharge delay time and uncertainty of breakdown voltage were taken as two important properties to measure the performance of the switch.