X-ray absorption tomography (X-ray tomography) is a non-destructive imaging technique that allows to obtain the external and internal 3D structures of a solid material. The lateral resolution of this analysis can go below the micrometer depending on the size and nature of the sample. X-ray tomography is used in many fields, from biology to aeronautics, from food processing to microelectronics... and on all types of samples. The analysis takes place in an atmosphere where temperature and humidity level can be controlled.
X-ray tomography is based on the multidirectional analysis of the interactions between the X-ray beam and the material. The transmitted radiation is recorded by the detector, providing a 2D X-ray image with grey contrasts depending on the attenuation of the X-ray beam by the different materials present in the sample. The absorption of this beam will be correlated to: the thickness, density and chemical composition of the observed areas.
The sample is positioned on a rotating plate, allowing the collection of these radiographs at different angles (from -180° to 180° or from -90° to 90°). The number of scans recorded as well as the chosen step are related to the resolution of the 3D reconstruction obtained.
The collected data will be processed with a reconstruction software giving access to a 3D visualization with the following information on the sample: shape, size, spatial distribution, heterogeneity and others (inclusions, pores, phases ...). The reconstructed object can then be manipulated in all spatial directions and, thanks to high resolution 3D imaging, sections can be made. It is also possible to perform dynamic measurements, when the kinetics of the chemical or physical phenomena of interest are compatible with the acquisition time of the technique.