Orientation independent ignitron

The orientation independent ignitron is a closing switch suitable for high average power and mobile applications. This report describes work performed to reduce the switch jitter and improve stability. Improvements are described which reduce switch rms-jitter times from 300 ns to less than 20 ns and enable run times to exceed 180 s at 100 p/s and 6-KW average power. These improvements include stabilizing the ignitor temperature by reducing the trigger energy from 2 J to 30 mJ. Stabilization of the background mercury pressure is also shown to lead to stabilization of the anode current pulse shape. Additional switch instabilities have been identified at higher average power. These instabilities are: (1) failure to trigger properly because contamination blocks mercury migration on the cathode surface, and (2) over-pressure breakdown caused by the evolution of contaminate gases of overheating of the cathode. A switch design is described which takes these factors into account and is estimated to have a 90-s stable run time with 30-kV, 15-kA, and 10-us pulses at 100 p/s.