Scanning X-ray interferometry over a millimeter baseline

A new translation device has been developed at the Istituto di Metrologia "G. Colonnetti" (IMGC) to improve the measurement of the (220) lattice spacing in silicon by X-ray/optical interferometry. It is capable of millimeter linear displacement and servo controls ensure picometer and nanoradian resolutions in crystal position and attitude. It has been successfully used to drive a scanning X-ray interferometer over a 2 mm displacement, thus extending by more than one order of magnitude the maximum crystal movement obtained before.