An ion implantation apparatus, system, and method are provided for transferring a plurality of workpieces between vacuum and atmospheric pressures, wherein an alignment mechanism is operable to align a plurality of workpieces for generally simultaneous transportation to a dual-workpiece load lock chamber. The alignment mechanism comprises a characterization device, an elevator, and two vertically-aligned workpiece supports for supporting two workpieces. First and second atmospheric robots are configured to generally simultaneously transfer two workpieces at a time between load lock modules, the alignment mechanism, and a FOUP. Third and fourth vacuum robots are configured to transfer one workpiece at a time between the load lock modules and a process module.