Improved brightness of the ATA injector

Conference · Tue Oct 01 00:00:00 EDT 1985 · IEEE Trans. Nucl. Sci.; (United States)

OSTI ID:5869126

Weir, J T; Caporaso, G J; Chambers, F W; Kalibjian, R; Kallman, J; Paul, A C; Prono, D S; Slominski, M E

Studies of the ATA injector using the low density plasma cathode (flashboard cathode) have shown that the brightness of the injector was being limited by the non-uniform emission of the cathode surface. To avoid this difficulty, we rearranged the cathode-anode geometry to accommodate field shaping surfaces and a field emission cathode. Computer simulations of the cathode-anode geometry using the EBQ code led us to try a 5.5 cm radius cathode with an A-K gap of about 13 cm. There was no grid used during the experiment. The cathode was surrounded by a Pierce correcting shroud and the typical gap voltage was about 2.5 MeV. Our initial tests of the field emission cathodes were done using a woven carbon yarn that was laced through a fine mesh screen and then trimmed to a uniform height. Using these ''tufted'' cathodes, it was easy to vary the number of emission sites per square centimeter. We also varied the geometry of these cathodes by giving the screen a slight convex shape so that the center of the cathode was about 1 cm closer to the anode plane than the edge of the cathode. At the suggestion of R. Adler of MRC, we also tested commerically available velvet cloth. This was done by epoxying the cloth to the cathode surface using a conducting silver epoxy. We tested the velvet cathodes in both the flat and convex configurations to compare with the tufted carbon yarn cathodes.

• Research Organization: Lawrence Livermore National Laboratory, University of California, Livermore, CA
• OSTI ID: 5869126
• Report Number(s): CONF-850504-; TRN: 86-017377
• Journal Information: IEEE Trans. Nucl. Sci.; (United States), Vol. NS-32:5; Conference: Particle accelerator conference, Vancouver, Canada, 13 May 1985
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
43 PARTICLE ACCELERATORS
ELECTRON BEAMS
BRIGHTNESS
LINEAR ACCELERATORS
ELECTRON BEAM INJECTION
BEAM PULSERS
CARBON FIBERS
CATHODES
COLLIMATORS
COMPUTERIZED SIMULATION
ELECTRON GUNS
MATERIALS TESTING
SCREENS
TEXTILES
ACCELERATORS
BEAM INJECTION
BEAMS
ELECTRODES
FIBERS
LEPTON BEAMS
OPTICAL PROPERTIES
PARTICLE BEAMS
PHYSICAL PROPERTIES
SIMULATION
TESTING
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