Breakdown and Recovery of a 250-kV Low-Pressure Spark Gap

Tests of an experimental low-pressure spark gap Blumlein switch are presented. Gas flows from a pulsed valve into the gap at a steady rate through holes in the cathode and results in a steady pressure of about 0.1 torr. The pressure outside the gap over the Blumlein insulator is much lower. Trigger electrodes are mounted in the grounded cathode. Initially the current rises exponentially with time with rate constant proportional to gas density. Measurements of rise time, jitter, and voltage holding recovery time are presented for charge voltages up to 250 kV for variations of charge time, gas density, gas type, and triggering method.