Effects of steady‐state electrical discharge on the separation of gas constituents in helium‐argon mixture

摘要

A study of gas separation (cataphoresis) has been made in the positive column of a steady‐state electric discharge, using the binary mixture 2.2% argon‐helium. A glow discharge is initiated in a 0.96‐m‐long tube of 9.5 mm diameter using a high‐voltage stabilized source. The discharge tube employs a brush anode and a brush cathode to obtain uniform discharge and is connected to a bakeable gas handling system. The discharge is scanned spectroscopically from anode to cathode and the emitted spectra of helium (5875) and argon (4152 Å) are monitored. The cataphoresis separation of the constituents is studied with variation of both the gas pressure and the current flowing between the electrodes. It has been found that the ratio of Ar/He increases with increasing distance from anode to cathode. Furthermore, the quality of cataphoresis improves with increasing pressure and current in accordance with theoretical predictions. The effect of the temperature of the walls on the quality of cataphoresis is investigated and found to decrease with increasing temperature in agreement with theory and with Schmeltekopf''s experimental study in helium‐neon mixtures.