Sub Microsecond Rise Time, 200kV Peak, Modular Solid State Trigger Unit for Rotating ARC Gap Switch Operation

A self-contained solid state trigger generator has been successfully implemented and life-tested with its companion rotating arc gap (RAG) coaxial switch. This is in response to CEA´s request for a cost-effective, reliable, and maintenance-free global switching solution for the upcoming LMJ Facility in France. The trigger unit provides > 200 kV peak trigger pulse with < 350 ns risetime (10% to 90%) at the output of a 3 m long RG-218 cable. The slew rate of the trigger pulse required is ~1 kV/ns @100 kV peak amplitude. These parameters, pre-determined via RAG switch trigger tests, are adequate for precise command firing the switch operating at M=4 (pressure set so operating voltage is 25% of self-break voltage at that pressure) value. With 480 each of these integrated switching systems required for the LMJ power conditioning units (PCU), reliability of the triggering system is paramount to the successful outcome of the laser fusion experiments. The adopted design is an all solid-state approach lending itself to potential applications where ruggedness, precision, long maintenance-free life, and high reliability are essential.