Characteristics of fast electrons from Grimm glow discharge He plasmas as an electron source

Abstract

In a study of d.c. helium Grimm glow discharges applied with a maximum high voltage of 5 kV, it was found that fast electrons emitted from the cathode surface passed right through the negative glow and the hollow anode. This fast electron current corresponds to approximately 50% of the discharge current at a high voltage of 5 kV and a low helium pressure of 0.43 Torr for an aluminium cathode. The characteristics of the fast electrons under various discharge conditions, i.e. for different cathode materials, discharge voltages and helium pressures, were investigated by measuring the electron-induced X-rays, in order to consider whether the glow discharge plasma could have an application as an electron source. It was found that fast electrons were generated more efficiently under a high voltage while using a low gas pressure in the aluminium cathode. The fast electrons were then used as an electron source for the electron-induced X-ray emission analysis of Fe-Mo binary alloys. This experiment indicated that fast electrons from a Grimm glow discharge plasma are useful as a simple and inexpensive electron source in electron-induced X-ray emission analysis.