Comparison of trigger requirements for gas switches for linear transformer drivers

Abstract

Linear Transformer Driver (LTD) technology is being developed for short pulse electron beam applications as well as high current Z-pinch drivers. Designs for both applications require low inductance spark gap switches which hold off 200 kV and trigger with low jitter. LTD cells or cavities typically contain many parallel switches which must close with low jitter to insure efficient operation of the system. The switch jitter must be much less than the risetime of the output pulse to prevent switches from firing after the peak in output power. Experiments with a 10-brick Ursa Minor cavity indicate that the switch jitter must be less than 2 ns to limit the late switch rate to less than 2%. Three swith designs have been tested in a single switch platform to evaluate switch jitter as a function of the peak trigger voltage, trigger pulse risetime, and switch pressure. Operating parameters were determined for each switch to meet the 2 ns jitter requirement.