Radioactive (tritium) ignitors for plasma limiters

Radioactive ignitors using tritium as the active material are shown to be a reliable electron priming source for the RF discharge gap in plasma limiters when cascaded with a diode limiter. This result is based on ion-chamber studies of priming current strength, electron distributions, and thermodynamic and chemical stability of titanium-tritide electron sources immersed in low-pressure gases. The results of -band measurements of the statistical distribution of output spike leakage amplitudes for overvolted discharge gaps and the threshold of breakdown of the RF gap in tuned plasma limiters containing titanium-tritide ignitors followed by a diode limiter show operating parameters equivalent to keep-alive plasma limiters. Experiments with the tritiated passive priming source substituted for the conventional dc keep-alive discharge show a greatly increased operating life in receiver protectors and gaseous TR\´s and the improvement of other important electrical parameters such as noise, reliability, and external driving power.