Uniformity Investigation of Barium Tungsten Cathode With Spherical Powder

A barium tungsten (Ba-W) cathode was successfully prepared with spherical W powder in this letter, and the porous matrix exhibited homogeneous pore distribution and good inter-pore connectivity. In the space charge limited zone, the cathode with spherical powder (Sph cathode) showed higher current density compared with the cathode with conventional powder. The practical work function distribution (PWFD) of Sph cathode was only 0.063 eV, which demonstrated this cathode had better emission uniformity. Ba coverage rate at pore ends made larger impact to the uniformity of work function distribution than the diffusion distance of Ba on the cathode surface.