Experimental study of the influence of the cathode in the characteristics of the cathode region

Abstract

Doppler free two photon optogalvanic measurements of the Stark splitting of the 2S level of hydrogen are used to determine the local electric field strength (E-field) in the cathode fall region of a hollow cathode discharge operated in pure hydrogen. The aim of these measurements is to study how the cathode fall characteristic depends on cathode material (stainless steel and tungsten) and cathode diameter (10 and 15 mm). The measurements revealed that the cathode diameter has a minor influence whereas the cathode fall characteristics obtained for stainless steel cathodes are remarkably modified due to sputtering.