An ion implantation apparatus including an enclosure defining a process chamber, a carriage slidably mounted on a shaft within the process chamber and coupled to a drive mechanism adapted to selectively move the carriage along the shaft. A platen assembly can be coupled to the carriage, and a linkage conduit can extend between a side wall of the enclosure and the carriage. The linkage conduit can include a plurality of pivotably interconnected linkage members that define a contiguous internal volume that is sealed from the process chamber. The contiguous volume can be held at a desired vacuum pressure separate from the vacuum environment of the process chamber.