Abstract: A series of long slats, preferably parallel and spaced apart uniformly, extend from a base plate to form a series of cavities between the slats for trapping high energy ions in the exit plume of an ion accelerator. The plume shield is designed to minimize escape of ions and sputtered atoms from the shield. The effectiveness of the shield in trapping and retarding ions and sputtered atoms can be accomplished by biasing the potential of the shield with respect to an adjacent structure and by inducing a magnetic field parallel to a target area of the shield, which can limit electron current to the target area.

Abstract: A specially designed magnetic shunt is provided encircling the anode region and/or annular gas distribution area of an ion accelerator with closed electron drift. The magnetic shunt is constructed to concentrate the magnetic field at the ion exit end, such that the location of maximum magnetic field strength is located downstream from the inner and outer magnetic poles of the accelerator. The specially designed shunt also results in desired curvatures of magnetic field lines upstream of the line of maximum magnetic field strength, to achieve a focusing effect for increasing the life and efficiency of accelerator.