...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 their 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 Hamamatsu detektor (CMOS flat panel sensor C7942SK-25, 2304 x 2304 Pixel, pixel pitch 50 µm) can be operated in double view mode.

Sample types and preparation

X-ray micro tomography can characterize all GEO-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 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).

Cone-beam geometry

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 density distribution within the object in the form of a digital image stack or as image volume, which can be downloaded from the lab server. A storage medium will not be provided. In addition, the transmission images can be supplied. Any anyalysis of the tomography data is possible in the context of a cooperation.

Contact person for technical information

Dr. Wolf-Achim Kahl

Analytical service

Requests for analyse services are welcome for both academic and industrial 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.).

User regulations µ-CT (only in German)