Apparatus for maintaining ion bombardment beam under improved vacuum condition

摘要

In an apparatus for bombarding a target with a beam of ions, an expedient is provided for maintaining the beam line and target under vacuum of 2x10-4 Torr. or lower pressures. The apparatus includes a mass separator, e.g., analyzing magnet adapted to provide selected ions which are to be formed into the desired beam with a trajectory along a selected axis: the target is positioned along this selected axis; the apparatus further includes: a housing extending from the mass separator to the target to enclose the axis and target within a chamber, beam defining means within said chamber traversing said axis and impeding the flow of gas through said chamber, said defining means having a beam defining opening therein at said axis to permit the passage of a selected portion of the beam toward the target, and vacuum drawing means connected to said chamber through an opening in said housing crossing said beam defining means whereby said drawing means removes gas from both sides of said beam defining means.