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...means X-ray 3D microtomography. We use a ProCon CT-ALPHA X-rays to inspect the three dimensional distribution of matter inside the object of investigation.
The method
The method is based on the detection and subsequent localisation of the degree of attenuation of the incident X-rays in the sample. The attenuation of X-rays by matter depends on both the chemical elements it consists of as well as the material density. The information about the varied X-ray absorption in encoded as grey values in the black-and-white images. Each image consists of voxels (volumetric pixels) and contains true volumetric information. The volume reconstruction allows, e. g., visualization of fabric compounds as 3D models, preparation of virtual thin sections in any desired direction, and quantitative analyses of volume and surface properties, or size-distribution of different fabric compounds.
The scanner
Our CT-ALPHA is equipped with a X-RAY WorX source (XWT-190-TCHE, 190 kV) that offers three different foci modes. Both a high-energy and a high-resolution target (W on diamond window) are in use. We can analyse both mm-sized samples with high resolution, and cm-sized samples with high energy. The Vieworks detektor (flat panel sensor VXTF-2532EAH, 2560 x 2048 Pixel, pixel pitch 124 µm) can be operated in double view mode.
Sample types and preparation
X-ray micro tomography can characterize all materials that are transparent for X-rays, e. g. silicates, carbonates, sulfates etc. The sample surface does not have to be prepared in advance. In our lab we analyze rocks with silicate, carbonate and sulfide minerals, volcanic pumice, foraminiferae, bivalves, organic samples like fish or rat bone, and more.
Sample size and -geometry
In general, samples of any shape can be investigated, however a cylindrical shape is most favorable. Sample size may range from a few millimeter to several centimeters. Most important for a successful scan is a sufficient transmission of the sample for X-rays. It is possible to scan selected sector of a sample (e. g., a micro core in a X-ray-transparent core holder).
What resolution can I expect?
Relevant for the attainable resolution is the position of the sample in the cone beam geometry between the X-ray point-focus source and the detector, which determines the magnification. In general, small samples (1-2 mm) can be characterised with high resolution (<1-3 µm per voxel), and larger samples with lower (20-40 µm per voxel).
The result
The result is the reconstructed spatial distribution of X-ray attenuation within the object, in the form of a digital image stack or as image volume that can be downloaded from the lab server. A storage medium will not be provided. In addition, the transmission images can be supplied. Any analysis of the tomography data is possible in the context of a scientific cooperation.
Contact person for technical information
Dr. Wolf-Achim Kahl
Analytical service
Requests for analyse services are welcome for both academic and non-commercial customers. Please contact
Prof. Dr. Wolfgang Bach (e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.) or
Dr. Wolf-Achim Kahl (e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.).