A Stabilized Switching Ignitron

Ignitrons switching high-current pulses are troubled by arc transfer to the wall. An ignitron was made with the anode closer to the cathode (1 cm) than to the wall (3 cm). It was tested successfully as a capacitor-bank crowbar (clamp) tube at 12 kv with two different current wave shapes. The first was 3 kiloamperes (ka) decaying with a 230-msec time constant (690 coulombs). The second was 55 ka decaying with a 12-msec time constant (660 coulombs). There was no indication of arc transfer damage on the wall. Also, as expected, the arc drop voltage decreased much faster (10 ¿sec vs 60 ¿sec) than a conventionally-spaced 5-inch ignitron and reached a 20% lower value.