Negative point-to-plane corona pulses in oxygen

Measurements have been made of the current pulses observed in a negative point-to-plane corona discharge in oxygen. The apparatus was constructed to ultra-high vacuum standards to ensure controllable conditions on the gas purity and the state of the electrode surfaces. The effects of cathode voltage, tip diameter and oxygen pressure on the current pulse shapes have been investigated. Results include the first report of a step on the trailing edge of corona pulses in pure oxygen. The dependence of the trailing edge plateau on several parameters has been measured. The results are compared with the theoretical predictions of Morrow (1985) where appropriate.