A five-axis computer-controlled stage for the Transmission Electron Microscope

Abstract

A new five axis computer controlled stage system for the transmission electron microscope has been developed. The current design uses the existing stage of a Philips 400T without internal modification. The motors are all synchronous and employ feedback control from shaft encoders rather than “steps”.The X and Y translation controls have an increment of 15 nm and are engaged by electronic clutches. The alpha tilt control can be incremented in 0.0625 degree units which allows 16 “steps” per degree. The beta tilt has an increment of 0.0017 degrees (approximately 500 counts per degree). The Z axis control has a 3 nm increment and can be controlled by a set of manual override switches. The position of the stage is monitored by shaft encoders in such a way that manual positioning does not effect motorized repositioning.All five axes are calibrated for speed to determine the log/linear range of movement (Figs. 1-4). From the graphs, three speeds are chosen.