EGU21-9974, updated on 18 May 2021
https://doi.org/10.5194/egusphere-egu21-9974
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Spectral X-ray computed micro tomography: a tool for 3-dimensional chemical imaging

Jonathan Sittner1,2, Margarita Merkulova2, Jose Ricardo da Assuncao Godinho1, Axel Renno1, Veerle Cnudde2,3, Marijn Boone4, Thomas De Schryver4, Denis Van Loo4, Antti Roine5, Jussi Liipo5, Bradley Martin Guy6, and Stijn Dewaele2
Jonathan Sittner et al.
  • 1Helmholtz-Zentrum Dresden-Rossendorf, Analytics, Freiberg, Germany
  • 2PProGRess-UGCT, Geology Department, Ghent University, Ghent, Belgium
  • 3Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands
  • 4TESCAN XRE, Ghent, Belgium
  • 5Metso-Outotec, Espoo, Finland
  • 6University of Johannesburg, Johannesburg, Republic of South Africa

Image-based analytical tools in geosciences are indispensable for the characterization of minerals, but most of them are limited to the surface of a polished plane in a sample and lack 3D information. X-ray micro computed tomography (micro CT) provides the missing 3D information of the microstructures inside samples. However, a major drawback of micro CT in the characterization of minerals is the lack of chemical information that makes mineral classification challenging.

Spectral X-ray micro computed tomography (Sp-CT) is a new and evolving tool in different applications such as medicine, security, material science, and geology. This non-destructive method uses a multi-pixel photon-counting detector (PCD) such as cadmium telluride (CdTe) in combination with a conventional CT scanner (TESCAN CoreTOM) to image a sample and detect its transmitted polychromatic X-ray spectrum. Based on the spectrum, elements in a sample can be identified by an increase in attenuation at specific K-edge energies. Therefore, chemically different particles can be distinguished inside a sample from a single CT scan. The method is able to distinguish elements with K-edges in the range from 25 to 160 keV, which applies to elements with Z > 48 (Sittner et al., 2020).

We present results from various sample materials. Different pure elements and element oxides were measured to compare the position of theoretical and measured K-edge energies. All measured K-edge energies are slightly above the theoretical value, but based on the results a correction algorithm could be developed. Furthermore, different monazite grains were investigated, which can be divided into two groups with respect to the content of different RE elements on the basis of the spectrum: La-Ce-rich and La-Ce-poor. In addition, samples from the Au-U Witwatersrand Supergroup demonstrate the potential applications of Sp-CT for geological samples. We measured different drill core samples from the Kalkoenkrans Reef at the Welkom Gold field. Sp-CT can distinguish gold, uraninite and galena grains based on their K-edge energies in the drill core without preparation.

Sittner, J., Godinho, J. R. A., Renno, A. D., Cnudde, V., Boone, M., De Schryver, T., Van Loo, D., Merkulova, M., Roine, A., & Liipo, J. (2020). Spectral X-ray computed micro tomography: 3-dimensional chemical imaging. X-Ray Spectrometry, September, 1–14.

How to cite: Sittner, J., Merkulova, M., Godinho, J. R. D. A., Renno, A., Cnudde, V., Boone, M., De Schryver, T., Van Loo, D., Roine, A., Liipo, J., Guy, B. M., and Dewaele, S.: Spectral X-ray computed micro tomography: a tool for 3-dimensional chemical imaging, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9974, https://doi.org/10.5194/egusphere-egu21-9974, 2021.

Corresponding presentation materials formerly uploaded have been withdrawn.