Thermionic cathode electron gun for high current densities
An electron gun using lanthanum hexaboride (LaB/sub 6/) as a cathode material is being studied for use as a robust thermionic emitter at high cathode current densities. It has a standard planar cathode, Pierce-type electron gun design with a space-charge-limited perveance of 3.2 x 10/sup -6/ A/V/sup 3/2/. Thus far it has been operated up to 36 kV in the space-charge-limited regime. The cathode is heated by electron bombardment and radiation from an auxiliary tungsten filament. The total heating requirement is found to be 202 W/cm/sup 2/ of cathode area at a cathode temperature of 1626/sup 0/C. These observations are found to be in reasonable agreement with a thermal steady-state power balance model. Beam current distribution measurements are made with a movable collector and Faraday cup, and are found to be in agreement with an electron-gun computer code. The cathode temperature distribution is also measured.
- Research Organization:
- Dept. of Electrical Engineering and Computer Science, Univ. of Michigan, Ann Arbor, MI 48109
- OSTI ID:
- 5884440
- Journal Information:
- IEEE Trans. Plasma Sci.; (United States), Journal Name: IEEE Trans. Plasma Sci.; (United States) Vol. PS-15:4; ISSN ITPSB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Molecular & Chemical Physics-- Beams & their Reactions
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700103 -- Fusion Energy-- Plasma Research-- Kinetics
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BEAM CURRENTS
BORIDES
BORON COMPOUNDS
CURRENT DENSITY
CURRENTS
DIODE TUBES
ELECTRON BEAM ION SOURCES
ELECTRON GUNS
ELECTRON TEMPERATURE
ELECTRON TUBES
ELEMENTS
ION SOURCES
LANTHANUM BORIDES
LANTHANUM COMPOUNDS
METALS
RARE EARTH COMPOUNDS
SPACE CHARGE
THERMIONIC DIODES
THERMIONIC TUBES
TRANSITION ELEMENTS
TUNGSTEN