Synchrotron X-Ray Microtomography Techniques Applied to the 3D Morphological and Textural Analysis of Geomaterials

English Abstract:

Imaging techniques play an important role in several research fields of the geosciences. The well known optical and scanning electron microscopy techniques are widely adopted tools for the investigation of the texture and morphology of rock samples. X-ray based techniques are also of particular interest and X-ray microradiography has proved to be useful for the analysis of soils.

In the last years a great interest has been posed on X-ray computed microtomography (micro-CT) techniques, based on both laboratory and synchrotron radiation sources, producing 3D images of the internal structure of objects with a spatial resolution at the micron- and submicron- scale. Investigations, performed directly in the 3D domain, overcome the limitations of stereological methods usually applied to microscopy-based measurements and enable to get images of the internal core of a sample by a non-destructive method, more suitable for further analyses and for precious or unique samples (archeological finds, fossils etc...). An intriguing challenge related to the use of micro-CT methods is to extract quantitative measures and indices directly from images data sets. Porosity and specific surface area as well as connectivity, tortuosity and anisotropy are interesting descriptors of a 3D model. To this purpose, we used the Pore3D software library developed at the Elettra-Sincrotrone Trieste laboratory (Italy) and specifically conceived for the handling of large 3D data sets. An open and customized software assures a complete control of the algorithm implementation and permits different strategies of analysis as a function of the specific scientific application.

Several applications of synchrotron X-ray micro-CT methodologies for the extraction of quantitative information from 3D images of geomaterials will be presented.