The conductivity of oxide cathodes. Part 5: Functional structure of the cathode

In this Part the oxide cathode operating at 1020°K is shown as 2-element device¿a thin-film cathodic-core thermionic emitter covered by a relatively massive porous oxide matrix. The thin-film emitter determines the total emission available from the cathode, and porous matrix settles the potential rise experienced by the current before it emerges into the outer vacuum. This potential rise is shown to depend only on the self-generated electron density within the matrix pores and to be largely independent of emission density from the core emitter.