Hollow-Cathode Glow Discharge in Hydrogen and the Noble Gases

Abstract

Properties of a discharge maintained between a planar anode and a cathode consisting of two parallel electrodes have been studied in helium, neon, hydrogen, and helium‐argon mixtures at pressures between 1 and 25 Torr. The analysis of the data led to the following main conclusions: (1) The enhancement of the discharge efficiency by the hollow‐cathode effect does not vary widely between the gases tested. (2) The presence of metastable excited atoms is not essential for a pronounced hollow‐cathode effect to occur. (3) The minimum distance from the cathodes at which the anode fall develops is a function of the cathode dimensions, and is simply related to changes in the electron concentration and average electron energy. (4) The lowest observed cathode fall for a hollow‐cathode discharge corresponded closely to the cathode fall of a normal plane‐cathode discharge. (5) The general nature of the hollow‐cathode effect in the gases tested is sufficiently similar to allow simple design criteria to be developed for plane‐parallel hollow‐cathode discharge tubes.