Phase Measurement X-Ray Interferometry

Abstract

A phase-step procedure is used with an x-ray interferometer to allow the use of standard phase-plot methods of fringe analysis. When used to measure displacement, this method allows more precise and reliable interpolation of fringe spacings than methods previously reported and is more tolerant of experimental uncertainties. Using the silicon (111) lattice planes as diffracting elements (period 0.3135625 nm), displacement measurements with a standard deviation of 0.003 nm can be routinely achieved. The experimental and data analysis methods required to achieve this resolution are reported.