The breakdown fields and risetimes of select gases under the conditions of fast charging (∼ 20 ns and less) and high pressures (20-100 atmospheres)

Abstract

An interest in wide-band impulse radar systems has brought about the need to develop phased antenna arrays that can focus and steer an electromagnetic pulse in the far field. To produce useful radiated signal levels in the far-field, these arrays will need to be driven by high voltage, high power sources that at least in the short term may rely on pulsers using gas spark gap technology. Since multiple pulsers will have to be used to drive a large array, a suitable pulser design will most importantly have to have ultra-low triggering jitter. A preliminary gas characterization investigation preceded the development of such a fast risetime, ultra-low jitter triggered spark gap based pulser. This paper describes the results of this investigation that looked at the breakdown fields and risetimes for a variety of commonly used gases in the field of pulse power. The gases studied included SF/sub 6/, air, 15 and 30% SF/sub 6//air mixes, nitrogen, and hydrogen. The goals of this investigation were to: characterize the breakdown field vs. pressure and examine the effects of: polarity, varying stress times, and uniform field vs. point-plane; and compare the actual measured resistive phase risetimes to calculations.