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Title: Production of N.sup.+ ions from a multicusp ion beam apparatus

Patent ·
OSTI ID:868720

A method of generating a high purity (at least 98%) N.sup.+ ion beam using a multicusp ion source (10) having a chamber (11) formed by a cylindrical chamber wall (12) surrounded by a plurality of magnets (13), a filament (57) centrally disposed in said chamber, a plasma electrode (36) having an extraction orifice (41) at one end of the chamber, a magnetic filter having two parallel magnets (21, 22) spaced from said plasma electrode (36) and dividing the chamber (11) into arc discharge and extraction regions. The method includes ionizing nitrogen gas in the arc discharge region of the chamber (11), maintaining the chamber wall (12) at a positive voltage relative to the filament (57) and at a magnitude for an optimum percentage of N.sup.+ ions in the extracted ion beams, disposing a hot liner (45) within the chamber and near the chamber wall (12) to limit recombination of N.sup.+ ions into the N.sub.2.sup.+ ions, spacing the magnets (21, 22) of the magnetic filter from each other for optimum percentage of N.sup.3 ions in the extracted ion beams, and maintaining a relatively low pressure downstream of the extraction orifice and of a magnitude (preferably within the range of 3-8.times.10.sup.-4 torr) for an optimum percentage of N.sup.+ ions in the extracted ion beam.

Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
DOE Contract Number:
AC03-76SF00098
Assignee:
United States of America as represented by United States (Washington, DC)
Patent Number(s):
US 5198677
OSTI ID:
868720
Country of Publication:
United States
Language:
English

References (3)

Small multicusp H source journal March 1988
Optimization of H production from a small multicusp ion source journal April 1989
Production of atomic or molecular nitrogen ion beams using a multicusp and a microwave ion source journal June 1988