Displacement measurements by a combined optical and x-ray interferometer(COXI)

A combined optical and x-ray interferometer(COXI) has been developed at KRISS to provide a means of calibration with sub-nanometer resolution up to the range of several hundreds of micrometers. Such calibration by the COXI using the lattice spacing of silicon is directly traceable to primary standards. The combined interferometer consists of three main components; an optical interferometer, an x-ray interferometer, and a translation stage. A very brief description of each component of the combined interferometer is presented. The optical interferometer of the COXI was compared with another laser interferometer and a capacitive sensor by measuring the displacement of the translation stage.