Microstructure analysis using visibility contrast in X-ray talbot interferometry

Abstract

We formulated reduction in visibility in the x-ray Talbot interferometer by the autocorrelation function of spatial fluctuations of a wavefront caused by unresolvable micron-size structures in a sample. The experimental results for several isotropic samples were well fitted by our formula with a simple model having three parameters characterizing the wavefront fluctuations: variance, correlation length, and the Hurst exponent. The Hurst exponent is relevant to the shapes of the microstructures, while the correlation length can be interpreted to their average size. Thus our results opens a new way to analyze microstructures in a sample. © 2011 American Institute of Physics.