In many research fields the use of micro and even sub-micron X-ray tomography has become an indispensable tool in acquiring and analyzing complex 3D structures. Especially in the field of material science, the non-destructive character of this technique has proven to be very valuable. Effectuating repetitive scans of material samples in different environmental conditions even permits in depth evaluation of physical material properties such as crack propagation and failure. However, applying a variable environment, whether mechanical loading, humidity or temperature changes is not straightforward in current CT-scanners. Standard micro-CT scanners are inconvenient because the sample has to rotate while in vivo-scanners have limited spatial resolution and are unpractical for applying external conditions.
During the last years, the centre for X-ray Tomography of Ghent University (UGCT) has specialized in designing dedicated high resolution CT scanners for laboratory research. Recently an environmental micro- CT scanner (EMCT) was developed at our facility with the purpose to permit easy, constant and automatic environmental changes during scan sessions for samples ranging from a few millimeters up to 15 cm in diameter. The EMCT works with fixed sample but rotating tube/detector structure.
The X-ray tube in the EMCT scanner is installed on a translation stage together with the detector, this stage is mounted on a rotating ring. By bringing the source closer to the sample, magnification is increased and therefore the spatial resolution. In addition, dedicated appendages have been developed to apply extreme conditions on the samples and both the scanner control software as well as the acquisition and reconstruction software that are in house developed, were adapted to this new way of semi-dynamic scanning. With these kind of setups, materials can be tested in an environment and under conditions close to what they endure in sito.