A method and apparatus 300 for better controlling scanning of a workpiece 330 through an ion beam path 306 provide for mounting a workpiece 330 on an elongated member, partially repetitively rotating the elongated member 500 around a point of rotation 368 to make repetitive scans of the workpiece 330 along and arcuate path 504 and bending the elongated member 500 at a joint 322 to move the one and out of the ion beam path 306 to facilitate attachment and removal of individual workpieces 330. A motor 315 used for the rotating may be suspended within a partial vacuum enclosure 304 against gravity for raising and lowering the elongated member and 500 a workpiece 306 for linear vertical scanning.