X-ray initiated uniform glow discharges

Uniform glow discharges with a volume of approximately 3 cm x 1 cm x 30 cm have been produced in CO2 at pressures between 200 and 760 torr or CO2, He N2 mixtures at total pressures up to 1200 torr, when breakdown was initiated by X-rays having a mean energy of about50 keV and pulse duration of about100 nsec. With a constant voltage applied to the electrodes, the onset of the discharge current occured about150 nsec from the rise of the X-ray pulse. A reduction in X-ray gun voltage resulted in multiple arcs and then to a localized arc. X-ray dosage was in the range of 1 to 2 mR/pulse for obtaining uniform glows and the glow discharges in CO2 mixtures yielded 10.6 μm output in an appropriate cavity