Abstract: An apparatus used to control a workpiece inside a vacuum chamber. The workpiece is supported on a workpiece holder in the vacuum chamber. The workpiece is isolated from the atmosphere outside of the vacuum chamber by differentially pumped vacuum seals and an integral air bearing support. The differentially pumped vacuum seals and integral air bearing support allow for multiple independent motions to be transmitted to the workpiece supported by the workpiece holder. The workpiece holder motions provided are (1) rotation about the X axis, (2) translation back and forth along the Y direction of an X-Y plane on the surface of the workpiece holder, and (3) rotation of the workpiece in the X-Y plane about its Z axis. Concentric seals, oval for the translation motion and circular for the rotational motion, are differentially pumped through common ports to provide successively decreasing pressure and gas flow in order to reduce the gas load into the vacuum vessel to a negligible rate.