Detection of individual sub-pixel features in edge-illumination X-ray phase contrast imaging by means of the dark-field channel

Abstract

We report on a direct comparison in the detectability of individual sub-pixel-size features between the three complementary contrast channels provided by edge-illumination X-ray phase contrast imaging at constant exposure time and spatial sampling pitch. The dark-field (or ultra-small-angle X-ray scattering) image is known to provide information on sample micro-structure at length scales that are smaller than the system's spatial resolution, averaged over its length. By using a custom-built groove sample, we show how this can also be exploited to detect individual, isolated features. While these are highlighted in the dark-field image, they remain invisible to the phase and attenuation contrast channels. Finally, we show images of a memory SD card as an indication towards potential applications.