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Author(s):
M. Sasao, H. Yamaoka, M. Wada and J. Fujita
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Title:
Direct Extraction of a Na- Beam from a Sodium Plasma
Date of publication:
July 1990
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Key words:
negative ion, sodium, volume production, hydrogen, Iithium, ion source
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Abstract:
Negative sodium ions (Na^-) were extracted from a small multi-cusp ion source. A steady state sodium plasma was produced by primary electrons in a sodium gas evaporating from a metal sample placed in the discharge chamber. The Na^- current density of I.5 muA/cm^2 was obtained from a single aperture of 1.5 mm diameter at relatively low discharge power of about 0.4 W and filament power of 50 W. Extraction characteristics were studied by changing the plasma electrode bias. The extracted Na^- current showed dependence on the bias voltage similar to that of H^- or Li^- volume production.
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