Neutralization of Space Charge Effects for Low Energy Ion Beams Using Field Emitters

The paper presents models and computations for neutralization of space charge effects using electrons provided by field emitter arrays. Different ion species (B-11(+), P-31(+), As-75(+)) with mergy in the range E-ion=200 eV-1 keV have been considered. The ion beam divergence is studied as a function of electron beam geometry and physical parameters (electron and ion energy, electron/ion current ratio I-e/I-ion). The electron beam geometry takes into account: electron source positions and initial launching angles. It is shown that optimal ion beam neutralization occurs for low energy electrons emitted. parallel to the ion beam.