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Electron emitting filaments for electron discharge devices

MetadataDetails
Publication Date2023-01-23
JournalOSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information)
AuthorsKa-Ngo Leung, Philip A Pincosy, K. W. Ehlers
InstitutionsAlamo Colleges, Ashland (United States)

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.degree. 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 non-uniform current distribution along the filament due to the emission of electrons from the filament.