PURPOSE: To keep the inside of an electron tube during driving at high vacuum and enable the extension of the life by depositing a chemically active material on the surface of a gate electrode provided opposite to the anode and applying a lower voltage to the electrode than the anode.
CONSTITUTION: An electron tube is composed of a base plate 1 such as glass, a contact electrode 2, micro chips 3 consisting of a high melting point metal such as W and Mo, directly provided on said contact electrode, an insulating layer 4 consisting of SiO2, a gate electrode 6 having pore 5 in the position corresponding to the micro chip 3, and an anode 7. The gate electrode 6 directly facing the anode 7 is formed of an alloy containing Ti and Zr or at least either of them. A lower voltage than the anode 7 is applied, and the ionized gas generated from the anode 7 is made into collision with the active material to provide a pure surface, by which the generated gas is adsorbed. Hence, a long-lived electron tube maintaining an ultra-high vacuum state can be obtained.
HASHIGUCHI JUNPEI
HAMADA KIYOSHI
KITAO SATOSHI
NONOMURA KINZO
