2009 Volume 44 Issue 3 Pages 199-205
The technique for measuring spatial distribution of X-ray attenuation coefficient is known as computed tomography. Recently, X-ray micro- and nanotomography techniques, which are sometimes combined with hard X-ray imaging microscopy, have been applied to the three-dimensional (3D) observations of micro- and nanoscopic features in materials. As is well known, the industrial X-ray tomography technique has been developed as well as that for medical diagnostic imaging. On the other hand, third-generation synchrotron radiation (SR) facilities such as the SPring-8 have been identified as an ideal source for X-ray tomography providing a high-energy X-ray beam with excellent lateral coherence and monochromaticity. Tomography performed utilizing SR facilities has enabled a reconstruction of volumes with the maximum spatial resolution of deep submicron level. Compared to the currently available other 3D visualization techniques, such as electron tomography, serial sectioning and neutron tomography, the X-ray tomography is clearly advantageous in the applicability to 4D (i.e. time being the fourth dimension with 3D space). The present authors have also proposed 3D/4D measurement procedures for various quantities, such as internal local crack driving force, 3D local stain and displacement fields, elemental concentration and crystallographic information, which would provide highly effective ways of assessing local phenomena quantitatively.
