Focused anode layer ion source with converging and charge compensated beam (falcon)

An ion sources comprising:

• a self-sustaining hollow cathode, wherein the hollow cathode is configured to allow the ion beam to pass, and wherein the hollow cathode is configured to form a self-sustaining plasma within the hollow cathode in the presence of both the ion beam and a positive potential at a surface of a substrate being treated by the ion beam.

A method of focusing an ion beam generated in a plasma accelerator with a closed electron drift and a narrow zone of acceleration, having an azimuthally closed discharge channel which extends continuously about a main axis, wherein the discharge channel has a top and bottom end and wherein the discharge channel has a slit providing an exit hole along the top end of the discharge channel, wherein the slit extends continuously about the main axis, the method comprising:

• tilting the slit to an angle which is greater than zero and less than 90° relative to the main axis;
• and
• providing a magnetic lens positioned outside the discharge channel along the slit wherein the magnetic lens is configured to magnetically focus the ion beam exiting the discharge channel.