MEASUREMENTS ON ELECTRON-BEAMS IN PULSED HOLLOW-CATHODE DISCHARGES

Two different regimes of electron beams have been reported in the pulsed hollow cathode discharge-a low-current, high-energy beam, and a relatively hi-current beam of low energy. The high-energy beam is related to the hollow cathode geometry and is found to be present even in the absence of subsequent gas breakdown, while the low-energy beam is always associated with voltage breakdown. In the present work, detailed measurements of the spatial and temporal distribution of the electron beam transported beyond a semi-transparent anode associated with gas breakdown are reported. In particular, a high-energy component is observed after electrical breakdown. Low-energy electron beams are observed to be transported beyond the anode throughout the main discharge period.