Low perverance ion beam extraction from an electron bombardment discharge

Conference · Tue Jan 01 04:00:00 EST 1974

OSTI ID:4071047

Seliger, R L; Ward, J W; Bakish, R ^[1]

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1. ed.

Ion beams extracted from an electron bombardment (Penning) discharge by low perveance, single aperture Pierce electrode configuration, are compared with the beam properties predicted by a space charge computer program. For a 1 mm diameter source aperture, and an electron perveance of 1 x 10$sup -8$ AV/sup - $sup 3$$/$$sub 2$/, the measured and computed results are in good agreement. When this configuration was scaled up to have a 4 mm diam source aperture the extracted current was as much as 40 percent higher than predicted by the calculated electron perveance of 1 x 10$sup -8$ AV/sup -$sup 3$$/$$sub 2$/. In the case of an electrode configuration with a calculated electron perveance of 3.5 x 10$sup -8$ A/V/sup $sup -3$$/$$sub 2$/, that was also scaled to a 4 mm diameter source aperture, the extracted current was also 40 percent higher than predicted. In the latter case at 70 kV a maximum beam current of 4.3 mA (or argon) could be extracted with 0.8 A of discharge current. Plasma sheath instabilities occurred at currents above approximately 2 times the calculated perveance. (auth)

• Research Organization: Hughes Research Labs., Malibu, CA
• NSA Number: NSA-33-015561
• OSTI ID: 4071047
• Country of Publication: United States
• Language: English

Related Subjects

*ION SOURCES-- BEAM EXTRACTION
640301* --Physics Research--Atomic
Molecular & Chemical Physics--Beams & Their Reactions
BEAM OPTICS
BEAM PRODUCTION
ION BEAMS
N60100* --Physics (Atomic & Molecular)--Atomic
Electron
Ion & Molecular Beams & Reactions
PERFORMANCE