A fast preionization source for diffuse discharges containing attachers

Diffuse discharge opening switches and most excimer lasers must operate with gas mixtures containing attachers. In self sustained discharges, preionization is required for arc free initiation of these discharges. The preionizer must have a short rise and falltime and must have an extremely accurate timing system because of the attachers in the discharge gas. Also, this device must have sufficient power to produce large volumetrically uniform electron densities in gases at pressures in the one atmosphere range.

This paper describes the design and construction of such a preionizer and gives an overview of various preionization techniques previously employed. The device presented here consists of eight coaxial cables for energy storage, which are switched through a master spark gap to eight cables terminated by individual multi-spark arrays. The preionizer and the main discharge are triggered by a single laser (with a beam splitter and with a variable optical delay on one of the beams). Experiments showing the influence of the delay, preionization pulse length, jitter, and durability of the spark sources on the main discharge are described.