IMPROVED ION SOURCE

摘要

An ion source utilizes independently powered electrodes isolated by a series of insulators. The ion source comprises an anode electrode with a hollow interior, where the anode is disposed between a cathode and an anti-cathode. A magnet imposes a magnetic field in an axial direction through the bore of the anode. The ion source includes a first voltage differential between the anode and cathode for the production of plasma and a second voltage differential between the anode and the anti-cathode for extraction of ions from the plasma, which ion beam is preferably of a narrow diameter at low beam energy. The voltage differential between the anti-cathode and anode is adjusted to control the initial beam divergence of extracted ions. An optional focus electrode with an independent power supply further focuses the ion beam.