Design Features of an Axial-Geometry, Plasma-Sputter, Heavy Negative Ion Source.

摘要

An axial-geometry, plasma-sputter, negative ion source, which utilizes multi-cusp, magnetic-field, plasma-confinement techniques, is under design at the Oak Ridge National Laboratory (ORNL). The source is based on the principles of operation used in a recently developed radial-geometry source which has demonstrated pulsed-mode peak intensity levels of several mA for a wide spectrum of heavy negative ion species. The pulsed-mode characteristics of the source are well suited for tandem electrostatic accelerator/synchrotron injection applications. Mechanical design features include provisions for fast interchange of sputter samples, ease of maintenance, direct cooling of the discharge chamber, and the use of easily replaced coaxial LaB(sub 6) cathodes. Principal features of the source will be described and the results of computational studies of the ion extraction optics will be presented. 15 refs., 5 figs., 1 tab.