PURPOSE: To obtain a cathode having highly reliable joint between a support and a filament, by employing the thermosetting resin as the material for the filament and the support and after securing the filament material to the predetermined position it is heated and carbonized to achieve the integrated structure.
CONSTITUTION: Both ends of a rectangular board is secured to a rectangular pole made of resin through an adhesives or the yet-hardened resin then the joint is hardened completely and heated in the vacuum to carbonize. Thereafter an insulator 8 made of ceramics is jointed to the central portion of said carbonized pole 7 while LaB6 single crystal 5 is grinded electrolytically in a nitric acid solution into a needle thus to produce a cathode. Consequently the electrical and mechanical jointing is performed completely resulting in the improvement of the reliability of the cathode.
KAWABE USHIO
KATSUTA TEIJI
TONOMURA AKIRA
