Small Back-Lighted Thyratrons

Summary form only given. We report studies of mini (6.3 mm diameter electrodes) back-lighted thyratron (BLT) switches, operating with currents up to 10 kA, and hold off voltages in excess of 40 kV for the mini-BLT. The pseudospark is a thyratron with a cathode variant: the cathode emission is provided by an initially hollow cathode mode that transitions to a self-heated super-emissive mode. As a result of this mechanism, the pseudospark does not require externally supplied power for heating the cathode. The BLT is an optically-triggered version of this switch. The switch studies reported here are of (optically triggered) BLTs with helium or hydrogen fill. Hold-off voltage and optical triggering studies of these small switches suggest that they can be optimized for miniaturized high voltage pulse generation. Overvolted operation was also studied for potential applications such as implementation into Marx generators. These studies suggest that the small pseudospark BLT represents progress towards ultra compact high peak power switches for compact repetitive pulsed power applications. Research to develop sealed versions will be reported, and a new plasma source based from the BLT structure will also be discussed.