Ion currents at the cathode in a Neminus;Ar abnormal glow discharge

摘要

A method for studying properties of the ion current to the cathode in mixedminus;gas coldminus;cathode discharges is discussed. Retarding potential measurements of the current through a small aperture in the cathode enables one to distinguish between currents due to different ion species provided the energy distribution of each ion species is different. This technique is applied to an abnormal glow discharge in Neminus;Ar Penning mixtures. It is found that at saturation of the Penning effect (at about 0.6percnt; argon in the mixture) nearly 70percnt; of the ion current to the cathode is due to Ar+ions.