Ion source with independent power supplies

摘要

An ion source is disclosed which utilizes independently powered electrodes that are isolated with 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 or electro-magnet imposes a magnetic field in an axial direction through the bore of the anode. Gas is introduced into the anode area at a controllable pressure. 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, forming an ion beam, which is preferably of a narrow diameter at low beam energy. In particular, 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. A final electrode defines the output boundary of the ion source to provide un-perturbed drift of the ions into the vacuum chamber.

主权项

1. An ion source comprising:
an anode, having a hollow interior region extending axially therethrough along a longitudinal axis; a magnet producing a magnetic field generally axially aligned with said hollow interior region of said anode; a cathode disposed along one end of said longitudinal axis, said cathode biased electrically negatively with respect to said anode; and an anti-cathode haying a first aperture, disposed along and coaxially aligned with a second end of said longitudinal axis, opposite said cathode with respect to said anode, said anti-cathode being separately and independently biased electrically negatively with respect to said anode and said cathode; said anode, cathode and anticathode forming a. chamber, including said hollow interior region of said anode, for the creation and constraint by contact with a plasma formed of charged ion particles; an electrode having a second aperture, disposed along and coaxially aligned with said second end of said longitudinal axis exterior to said anti-cathode, said electrode being separately and independently biased electrically negatively with respect to said anode, said cathode and said anti-cathode; and said magnetic field and said bias of said cathode, anticathode and electrode, causing said charged ion particles to form a focused beam along said longitudinal axis which passes through said first and second apertures.