Electron emitting filaments for electron discharge devices
Abstract
Electrons are copiously emitted by a device comprising a loop-shaped lament made of lanthanum hexaboride. The filament is directly heated by an electrical current produced along the filament by a power supply connected to the terminal legs of the filament. To produce a filament, a diamond saw or the like is used to cut a slice from a bar made of lanthanum hexaboride. The diamond saw is then used to cut the slice into the shape of a loop which may be generally rectangular, U-shaped, hairpin-shaped, zigzag-shaped, or generally circular. The filaments provide high electron emission at a relatively low operating temperature, such as 1600(0)C. To achieve uniform heating, the filament is formed with a cross section which is tapered between the opposite ends of the filament to compensate for nonuniform current distribution along the filament due to the emission of electrons from the filament.
- Publication:
-
Patent Application Department of Energy
- Pub Date:
- June 1983
- Bibcode:
- 1983doe..reptR....L
- Keywords:
-
- Electric Discharges;
- Electron Emission;
- Ion Sources;
- Borides;
- Fabrication;
- Heating;
- Lanthanum Compounds;
- Patent Applications;
- Electronics and Electrical Engineering