An ultra compact back-lighted thyratron for nanosecond switching applications

Abstract

An ultra-compact back-lighted thyratron (BLT), which is also named as mini-BLT, with effective volume of 15 cm 3 was developed to serve as a high voltage switch in compact transient plasma ignition systems. The mini-BLT can hold off 40 kV and was used to conduct a peak current up to 4.5 kA. A 30 ns switching delay with 2 ns jitter was achieved when triggered by a 70 mJ, 355 nm laser pulse. Delay and jitter increase as the photon energy of the trigger pulse decreases. The plasma density in the switch measured at a peak current of 3.2 kA is 9×10 14 cm -3 . The mini-BLT was successfully used as the switch in a 100 ns, 60 kV pulse generator for generation of streamers in a plasma ignition system.

An Ultra Compact Back-Lighted Thyratron

“…For the hold-off voltage less than 10 kV, which corresponds to >1100 mTorr for the helium-fill or >600 mTorr for the hydrogen-fill, 10% variation of the mean was recorded. [1] 300 400 500 600 700 800 900 1000 1100 1200…”

“…An ultra-compact BLT (mini-BLT) with the effective electrode volume of 15 cm 3 was engineered [1]. The schematic of the dismountable mini-BLT and its testing circuitry are shown in Figure 1.…”

“…The mini-BLT filled with helium was integrated into a pulsed power supply, as shown in Figure 2, to generate 60 kV, 100 ns voltage pulses at a 100 ohm load. This pulse generator was able to initiate nanosecond transient plasmas for combustion ignition [1].…”

“…Mini-BLT and the testing circuitry[1] Schematic of a mini-BLT-switched pulsed power generation circuitry for plasma assisted combustion ignition[1] …”

“…Delay and jitter of the mini-BLT, filled with He at 800 mTorr, as a function of the pulsed laser triggering energy (5 ns at 355 nm). Each data point was the average of 20 measurements [1]. …”