Small BLT switches for compact pulsed power applications

This paper reports initial design and testing of a compact back-lighted thyratron (BLT) switch with a 12.7 mm o.d. glass envelope. The total switch size, 25 cm³, was reduced by more than one order of magnitude relative to previously published versions of the switch. A broad operation range, from 100 mTorr to 1000 mTorr, was measured with the hold-off voltage staying almost constant at 20 kV in helium. Operation as a BLT, with UV light incident on the back surface of the cathode, was also studied. The current rise rate was measured to be 1times10¹¹ A/s with a switch hold-off voltage of 17 kV when triggered by a 266 nm laser pulse with an effective optical energy less than 10 mJ. The trigger delay time was measured to be 85 ns with a jitter of less than 10 ns. The switch lifetime was tested for 10⁶ discharges at a repetition rate of 10 Hz without significant decay of switch performance. The development of the small BLT switches will benefit compact pulsed power technologies and their applications