Pulsed intense electron beams produced in high voltage hollow cathode discharges: a comparative study

Summary form only given, as follows. Intense pulsed electron beams with remarkable parameters are generated in high voltage (5-30 kV) transient hollow cathode discharges (THCD). Due to their high current (50-1000 A), high power density (up to 10/sup 9/ W/cm/sup 2/) and small diameter (0.2-2 mm), these high brightness beams were successfully tested in applications such as material processing, thin film technologies, intense soft X-ray sources, charged particle sources for accelerators and others. The most efficient THCD configurations for generating such electron beams are the pseudospark, the channel spark and preionization-control led open-ended hollow-cathode (PCOHC) configurations. These configurations differ one from another mainly in discharge geometry and typical gas pressure. The THCD configurations were optimized lately to increase the intensity of the generated electron beams. Beam parameters such as current, pulse length, and electron energy are measured for all three configurations using the same diagnostics. Fast shutter photography is used to study the time and space resolved characteristics of the plasma dynamics. The dependence of the beam parameters on discharge geometry, voltage, external capacity and gas pressure is compared in all three configurations. An overview of the electron beam parameters obtained in the pseudospark, channel spark and PCOHC configurations is presented.