Controlled porosity cathodes for high current density, long life application

Calabazas Creek Research, Inc. (CCR) is developing controlled porosity cathodes by sintering tungsten wires to create a cap over a reservoir of barium oxide, calcium oxide, and aluminum oxide. The result is a uniform array of pores for uniform emission and a large supply of barium compound for long life operation. The barium diffusion rate can be controlled by the size of the pores and the thickness of the reservoir cap. This makes it possible to tailor the cathode for a specific current density and lifetime. It is anticipated that emission densities approaching 100 A/cm2 are feasible. Experiments are planned to determine the ultimate current density capability.