| 摘要 |
A method of manufacturing an emitter (8; 10) for a thermionic dispenser cathode, includes forming a porous emitter body with substantially interconnected pores, having an emission surface (11; 16) from which, upon application of heat, electrons are emitted. The porous emitter body is suitable for transporting through the substantially interconnected pores, a compound released upon application of heat, to the emission surface (11; 16), which compound, when deposited on the emission surface (11; 16), serves to lower an effective work function of the emitter (8; 10). The porous emitter body is formed by means of a process of deposition of material. At least a region of the porous emitter body is provided with a continuously varying porosity. The porosity is continuously varied by controlling at least one parameter of the deposition process. |
