Mechanism of High-Efficiency Electron Beam Generation in a High-Voltage Discharge in Helium and Its Mixtures with Oxygen and Nitrogen

The results of investigation of the current-voltage characteristics (CVCs) and electron beam generation efficiency in continuous discharges in helium, its mixtures with oxygen and nitrogen, as well as in pure oxygen and helium are presented. Peculiarities of CVCs are singled out and interpreted in terms of a changed role of the principal emission mechanisms with an increase in the voltage. It is shown that a high efficiency of the electron beam generation of more than 80% can be achieved in glow discharges in helium, oxygen, and nitrogen. In helium, it is provided by the predominating photoemission, while in oxygen and nitrogen and their mixtures with helium – mainly by the kinetic emission under the impact of fast heavy particles.