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

摘要

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.

主权项

1. An X-ray arrangement for obtaining quantitative X-ray images from a sample, comprising:
a) an X-ray source; b) a set of at least two gratings; c) a position-sensitive detector with spatially modulated detection sensitivity having a plurality of individual pixels; d) a recorder connected to said detector for recording images of said detector; e) evaluation means for evaluating respective intensities for each pixel in a series of images in order to identify a characteristic of the object for each individual pixel as one or more of an absorption-dominated pixel or a differential phase contrast dominated pixel or an x-ray scattering dominated pixel; f) wherein the series of images is collected by continuously or stepwise rotating from 0 to π or 2π either the sample or the X-ray source relative to the sample; g) said set of gratings, or part of said gratings being manufactured with planar geometry where the X-rays pass through said gratings parallel to the substrate; h) said grating structures extending along an x-ray path which determines the phase shift and attenuation that said grating structures cause to the x-rays, not being given by the thickness of said structures, but by a length of said grating structures; and i) wherein a combination of said grating structures of said set of gratings are fabricated on a single substrate.