DIRECTLY HEATED THERMIONIC CATHODE Russian patent published in 2023 - IPC H01J1/15 H01J1/13 

FIELD: electronic engineering.

SUBSTANCE: at the top of a direct-heated thermionic cathode made of tungsten or lanthanum hexaboride wire in the form of a U-shaped arc with its ends attached to metal holders mounted in a disk of dielectric material, a limited section of the cathode with a smaller diameter d is formed at the bend of the wire, which will be heated to the incandescent temperature of thermionic emission not over its entire length. This section is limited at both ends by a wire with a diameter D>d. The length of the limited section of the cathode emitting electrons with a smaller wire diameter is limited by the relation 5d≥L≥2d, which is determined by the technological capabilities of its implementation.

EFFECT: simplification of the cathode design with localization of thermionic emission on a limited area of the cathode surface.

1 cl, 1 dwg