Electron emitting filaments for electron discharge devices
Electrons are copiously emitted by a device comprising a loop-shaped filament 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/sup 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.
- DOE Contract Number:
- AC03-76SF00098
- Assignee:
- Dept. of Energy
- Patent Number(s):
- None
- Application Number:
- ON: DE84011098
- OSTI ID:
- 6969013
- Country of Publication:
- United States
- Language:
- English
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Directly heated lanthanum hexaboride filaments
Electron emitting filaments for electron discharge devices