CONTROL OF DISCHARGE IN HIGH VOLTAGE FLUID INSULATION

An instrument is provided which produces ionizing radiation. The instrument includes a high voltage source of charge and ionizing radiation. The instrument further includes a housing filled with insulating gas and containing the high voltage source. The instrument further includes an insulator to which the high voltage source is mounted so that the source is spaced from the housing. The instrument further includes one or more collector electrodes arranged in the housing such that the high voltage source preferentially discharges to the collector electrode(s). The instrument further includes a control system which determines a level of ionization of the insulating gas through the amount of discharge to the collector electrode(s). The instrument further includes discharge rate limiting means controllable by the control system to deionize the insulating fluid at a controlled discharge rate and thereby maintain the maximum rate of discharge below a predetermined current. In this way, breakdown events can be inhibited.