Low-energy ion beam extraction and transport: Experiment--computer comparison

Journal Article · Fri Apr 01 04:00:00 EST 1994 · Review of Scientific Instruments; (United States)

DOI:https://doi.org/10.1063/1.1144937· OSTI ID:5095200

Spaedtke, P ^[1]; Brown, I; Fojas, P ^[2]

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1. Gesellschaft fuer Schwerionenforschung (GSI), PF 110552, D-64220 Darmstadt (Germany)
2. Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States)

Ion beam formation at low energy ([similar to]1 keV or so) is more difficult to accomplish than at high energy because of beam blowup by space-charge forces in the uncompensated region within the extractor, an effect which is yet more pronounced for heavy ions and for high beam current density. For the same reasons, the extracted ion beam is more strongly subject to space charge blowup than higher energy beams if it is not space-charge neutralized to a high degree. A version of vacuum arc ion source with an extractor that produces low-energy metal ion beams at relatively high current ([similar to]0.5--10 kV at up to [similar to]100 mA) using a multi-aperture, accel--decel extractor configuration has been created. The experimentally observed beam extraction characteristics of this source is compared with those predicted using the AXCEL[minus]INP code, and the implied downstream beam transport with theoretical expectations. It is concluded that the low-energy extractor performance is in reasonable agreement with the code, and that good downstream space charge neutralization is obtained. Here, the code and the experimental results are described, and the features that contribute to good low-energy performance are discussed.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5095200
• Journal Information: Review of Scientific Instruments; (United States), Journal Name: Review of Scientific Instruments; (United States) Vol. 65:4; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

661220* -- Particle Beam Production & Handling
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BEAM CURRENTS
BEAM EXTRACTION
BEAM TRANSPORT
BEAMS
COMPUTER CODES
CURRENTS
ELECTRIC ARCS
ELECTRIC CURRENTS
ELECTRIC DISCHARGES
ELEMENTS
ION BEAMS
ION SOURCES
METALS
MILLI AMP BEAM CURRENTS
SPACE CHARGE
Ta
Targets-- (1992-)