Electron emitting filaments for electron discharge devices

Patent · Thu Dec 31 23:00:00 EST 1987

OSTI ID:866656

Leung, Ka-Ngo ^[1]; Pincosy, Philip A ^[2]; Ehlers, Kenneth W ^[3]

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1. Hercules, CA
2. Oakland, CA
3. Alamo, CA

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.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA
• DOE Contract Number: AC03-76SF00098
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4760306
• OSTI ID: 866656
• Country of Publication: United States
• Language: English

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