Probing the structure of heterogeneous diluted materials by diffraction tomography

Area of Science:

• Materials Science
• Nanoscience
• Analytical Chemistry

Background:

• Characterizing heterogeneous and ill-ordered materials requires advanced local structural probes.
• Existing methods like X-ray diffraction have limited detection sensitivity, while transmission electron microscopy requires destructive sample preparation.
• Materials properties are intrinsically linked to their structural heterogeneity and hierarchical organization across multiple scales.

Purpose of the Study:

• To develop and demonstrate a non-invasive method for analyzing unidentified phases in nanomaterials and polycrystalline materials.
• To overcome the limitations of existing structural characterization techniques.
• To enable multimodal analysis for comprehensive materials investigation.

Main Methods:

• Coupling pencil-beam tomography with X-ray diffraction (XRD).
• Applying the method to a high-pressure carbon phases pellet and a heterogeneous powder (chalcedony and iron pigments).
• Simultaneous data acquisition with X-ray fluorescence, Compton, and absorption tomographies.

Main Results:

• Achieved non-invasive structural refinement with a weight sensitivity of one part per thousand.
• Successfully extracted scattering patterns from amorphous and crystalline compounds with similar densities and compositions.
• Demonstrated the capability to analyze complex heterogeneous samples.

Conclusions:

• The combined diffraction-tomography approach is a powerful tool for characterizing diverse materials, including nanomaterials and complex mixtures.
• This multimodal technique offers significant advantages over conventional methods, particularly for sensitive and non-destructive analysis.
• The method has broad applicability across materials science, geology, environmental science, and cultural heritage studies.