Characterization of oriented microstructures through anisotropic small-angle scattering by 2D neutron dark-field imaging

Within neutron imaging, different methods have been developed with the aim to go beyond the conventional contrast modalities, such as grating interferometry. Existing grating interferometers are sensitive to scattering in a single direction only, and thus investigations of anisotropic scattering structures imply the need for a circular scan of either the sample or the gratings. Here we propose an approach that allows assessment of anisotropic scattering in a single acquisition mode and to broaden the range of the investigation with respect to the probed correlation lengths. This is achieved by a far-field grating interferometer with a tailored 2D-design. The combination of a directional neutron dark-field imaging approach with a scan of the sample to detector distance yields to the characterization of the local 2D real-space correlation functions of a strongly oriented sample analogous to conventional small-angle scattering. Our results usher in quantitative and spatially resolved investigations of anisotropic and strongly oriented systems beyond current capabilities. Acquiring orientation-resolved neutron images currently requires the sample or system to be rotated, precluding single-shot measurement. Here, the authors achieve small-angle scattering information with spatial resolution in a single shot through the inclusion of a circular diffraction grating.