High-current density, high-brightness electron beams from large-area lanthanum hexaboride cathodes
Large (approx.5 cm) diameter lanthanum hexaboride (LaB/sub 6/) cathodes operated at 10 kV have produced 1--5-..mu..s electron pulses with current density between 10 and 20 A/cm/sup 2/. Normalized beam brightness, B/sub n/ = I/(..pi beta gamma..epsilon)/sup 2/, approximately 3 x 10/sup 5/ A/cm/sup 2/ rad/sup 2/ has been consistently measured. To obtain this high-current density, the LaB/sub 6/ cathodes have been heated to temperatures between approx.1600 and 1800 /sup 0/C. Very uniform temperature profiles are obtained by applying a carefully tailored electron bombardment heating power distribution. These measurements have been made between pressure 10/sup -6/--10/sup -5/ Torr, i.e., under much less demanding vacuum conditions than that required by conventional dispenser-type cathodes.
- Research Organization:
- Advanced Beam Technologies Branch, Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375
- OSTI ID:
- 5268534
- Journal Information:
- J. Appl. Phys.; (United States), Vol. 63:8
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
ELECTRON BEAMS
BRIGHTNESS
CATHODES
LANTHANUM BORIDES
ELECTRON EMISSION
BEAM PRODUCTION
CURRENT DENSITY
ELECTRON SOURCES
EXPERIMENTAL DATA
FREE ELECTRON LASERS
OPERATION
VERY HIGH TEMPERATURE
BEAMS
BORIDES
BORON COMPOUNDS
DATA
ELECTRODES
EMISSION
INFORMATION
LANTHANUM COMPOUNDS
LASERS
LEPTON BEAMS
NUMERICAL DATA
OPTICAL PROPERTIES
PARTICLE BEAMS
PARTICLE SOURCES
PHYSICAL PROPERTIES
RADIATION SOURCES
RARE EARTH COMPOUNDS
640301* - Atomic
Molecular & Chemical Physics- Beams & their Reactions