Low inductance switching studies for Linear Transformer Drivers

We are developing new low-inductance gas switches for Linear Transformer Drivers (LTDs). Linear Transformer drivers are a new pulsed-power architecture that may dramatically reduce the size and cost of future pulsed-power drivers, but which place stringent requirements on gas switches. A typical large LTD may have 10,000 or more gas switches that are DC-charged to 200 kV and that must be triggered with a jitter of 5-ns or less with a very low prefire rate. We are studying new air-insulated gas switches with total inductances of 68-90 nH. These switches transfer 100 J of stored energy for thousands of shots. Typical 10%-90% current rise-times are less than 50 ns and peak currents are on the order of 40 kA into a matched load. One of the switches has a 1-sigma jitter less than 800 picoseconds. Since triggering 10,000 or more switches is a significant challenge, we are also making a detailed study triggering requirements for these switches. We have previously reported tests of four competing switches for LTDs. In this article we report new tests on improved versions of two of the four switches described previously.