IMPREGNATED CATHODE STRUCTURE, CATHODE SUBSTRATE USED FOR THE STRUCTURE, ELECTRON GUN STRUCTURE USING THE CATHODE STRUCTURE, AND ELECTRON TUBE

摘要

An impregnated cathode structure using an impregnated cathode substrate which includes a large grain size, low porosity region and a small grain size, high porosity region disposed on the side of an electron emission surface of the large grain size, low porosity region, having a mean grain size smaller than a mean grain size in the large grain size, low porosity region and having a porosity greater than the porosity in the large grain size, low porosity region, and which is impregnated with an electron emission material.