Time Changes in Emission from Oxide-Coated Cathodes

Abstract

The decay of electron emission which sets in when emission-limited current is drawn from an oxide cathode has been studied as a function of anode voltage, anode current, cathode temperature, and tube temperature. It is concluded that the decay is due to a transport of barium or oxygen by electrolysis and diffusion. A value is deduced for the heat of the diffusion process. Other time variations in emission have been observed and are discussed.