Grating-Based X-Ray Computed Tomography for Improved Contrast on a Heterogeneous Geomaterial

Abstract

Phase-contrast X-ray imaging has shown its potential to capture at micrometric scale and in three dimensions (3D), the structure and deformation of poorly-absorbing soft materials such as polymers and biological structures. When composed of constituents that attenuate X-rays differently, heterogeneous hard materials are often well resolved in 3D using absorption-based X-ray computed tomography (CT) techniques. As a result, phase-contrast techniques have been less frequently used to image such materials. However, many geomaterials contain similarly X-ray attenuating constituents, thereby complicating the use of absorption-based X-ray CT methods. Here we present the innovative use of grating-based synchrotron radiation computed tomography, a phase-sensitive technique, in order to better identify the distribution of constituents within geomaterials. We show that this approach enhances the contrast between similarly X-ray absorbing constituents, and can be used to identify spatially small structures such as pores or mineral grains that are typically poorly resolved with conventional absorption-based X-ray CT.

First application of scintillator-based photon-counting computed tomography to rock samples: Preliminary results and prospects

“…Phase-contrast X-ray imaging that utilizes contrast changes caused by X-ray phase shift and refraction when X-rays pass through material (e.g., Davis et al, 1995;Momose, 1995;Momose et al, 1996) is another powerful technique to better define the spatial distribution of constituents in geological materials, even in phases with weak absorption (Zandomeghi et al, 2010;Moore et al, ,2022).…”