酸化物陰極の電子衝撃効果
1954 年 23 巻 12 号 p. 566-569
詳細
1954 年 23 巻 12 号 p. 566-569
The change of thermionic emission patterns from oxide-coated cathode was by Johnson-Schockley type emission microscope. It is the general characteristics that the oxide-coated cathode is activated after the electron bombardment. It will be possible to suppose that barium oxide dissociates into barium atoms and oxygen molecules by electron bombardment, and thus layers of excess barium atoms are formed on the oxide-coated cathode, whereas the oxygen molecules formed may de liberated from the surface. Barium atoms thus pro-duced on the oxide-coated cathode surface, at a comparatively higher temperature or electric field, can diffuse easily into barium oxide cathode and compose the impurity centre gradually. It is also found that the dissociation probability changes with the activation degree of barium oxide and has a structure sensitive character.
