Multi-scale characterisation by integrating SAXS with phase-contrast and dark-field imaging

Standard X-ray radiography often struggles to differentiate materials with similar absorption properties, limiting the level of insight it can provide. Phase-contrast (PC) imaging and dark-field (DF) imaging are innovative new X-ray imaging modalities that overcome these limitations and open new perspectives for sample characterization.

Phase-contrast imaging detects subtle refraction of X-rays within a sample, sharply enhancing interfaces and boundaries that are almost invisible in attenuation images.

Dark-field imaging is sensitive to ultra-small-angle scattering events, providing full-field maps of nanoscale heterogeneities and orientation effects.

Figure 1. Schematic of a speckle-based X-ray imaging setup showing reference and sample images.

The combination of these two modalities enables researchers to reveal hidden structural features, distinguish between otherwise indistinguishable materials, and connect macroscopic visualization with nanometric detail.

Figure 2. Attenuation (a), phase (b), dark-field (c), and directional dark-field (d) images of a nylon wire and carbon fiber bundles. While attenuation imaging does not distinguish the materials, phase-contrast and dark-field imaging highlight differences in composition, nanostructure, and orientation.

The DF-PCI option developed by Xenocs on the Xeuss instruments extends these imaging capabilities even further by uniquely integrating them with SAXS. This makes it possible to correlate full-field contrasts with quantitative nanostructural information, providing a comprehensive understanding of materials across length scales.