Plume shield for ion accelerators

The present invention relates to a system for protecting structures or components adjacent to ion accelerators from erosion or other damage by impact of accelerated ions with such structures and/or by impact by sputtered atoms resulting from the accelerated ions contacting other surfaces. 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.