Method for x-ray phase contrast and dark-field imaging using an arrangement of gratings in planar geometry

Abstract

An X-ray arrangement is suitable to record absorption, phase contrast, and dark field images of an object. The visibility of low absorbing specimens is improved and required radiation dose is reduced. The assembly includes an X-ray source; two or more gratings; a position-sensitive detector with spatially modulated detection sensitivity; a recorder for recording the images; an evaluator for evaluating the intensities for each pixel to identify the characteristic of the object for each individual pixel as an absorption and/or a differential phase contrast and/or an x-ray scattering dominated pixel. Images are collected by rotating from 0 to n or 2n either the sample or the assembly. The gratings are produced with planar geometry. The X-rays pass through the gratings parallel to the substrate. The grating structures extend along the X-ray path which determines the phase shift. The attenuation of the X-rays caused by the grating structures is no longer given by the thickness, but by the length of the grating structures.