Ultra-high resolution X-ray micro-computed tomography

The Department of Earth Sciences is home to a Skyscan 1173 ultra-high resolution X-ray micro-computed tomography (XR-µCT) laboratory for Earth material research. Using higher-energy X-rays and longer dosage times than conventional X-ray tomography facilities, the XR-µCT lab allows to non-destructively study the interior of solid matter at ultra-high resolution. Direct applications of XR-µCT in the Earth Sciences improve our knowledge of the 3-D distribution of ore minerals in rocks, help to analyse pore structures in rocks relevant for hydrocarbon reservoirs or water pathways, and assist in the imaging and examination of rock fractures and their potential for transport or storage of contaminants such as nuclear waste and heavy metals.

Besides rocks, the XR-µCT lab allows to study a wide range of decimetre-sized dense solids including fossils, bones, and engineered materials. The maximum length of a sample that can be scanned is 15 cm and the maximum scan diameter is 14 cm (max. sample size that fits into sample chamber: 20 cm x 14 cm). Smaller specimens can also be studied at a maximum resolution of less than 5 µm.

The key components of the XR-µCT system include (1) a 40-130 keV micro-focus (< 5 µm) X-ray source, (2) a distortion-free 2240 x 2240 pixel flat-panel X-ray sensor, (3) a micro-positioning sample stage that can handle also heavy (several kg) objects, and (4) a data acquisition, reconstruction and image processing system that renders a 3-D image of the sample interior. While the sample is illuminated by an X-ray cone beam, the sample rotates around its vertical axis so that hundreds of angular views can be detected. Each view is a magnified projection image and corresponds to a virtual cross-section slice through the sample monitoring the details of its internal structure. These details reflect the 2-D spatial distribution of X-ray attenuation of the sample interior which is directly related to variations in density and chemical composition.

Applications from academic research within and beyond Carleton University as well as from government agencies and industry are welcome. Imaging services can be provided according to the rate schedule given below. Please contact me directly for more information (fred_gaidies.at.carleton.ca).

 

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  CT24_99

The image to the left shows a 3D rendered model of the interior of a garnet schist from the Sikkim Himalayas (India). The cylindrical sample has a diameter of ca. 1.5 cm and is composed of garnet (red) and chlorite (green) in a matrix of white mica and biotite (grey). Voids in the model are occupied in the rock by quartz and plagioclase.

Please click on the image to view an animated 3D model of this sample (9 MB).

     

CT24_99

This image shows a 3D rendered model of the distribution of different sulphides (yellow and silver) in half of a drill core (diameter ca. 5 cm) of a syenite (sample courtesy of Dr. Nadine Wittig, Carleton U.). Note that some of the sulphide crystals precipitated along a plane which can be seen at 00:06 and 00:32 in the animated 3D model of this sample (5 MB).

 
 
CynopsPyrrogaster
 
This is the skull of an adult fire belly newt (Cynops pyrrogaster), Canadian Museum of Nature specimen CMN 25890 (research by Dr. Hillary Maddin, Carleton U.). This salamander is native to Japan and China, and is known for its brightly coloured belly that warns predators of its toxicity. Click here for a 3D model of this skull (6 MB).
 

Current Rate Schedule (effective May 22, 2017)

User fees cover expenses associated with data acquisition (including specimen mounting, instrument calibration and scanning) and data reconstruction (conversion of raw CT data into imaginary slices, artifact reduction, data transfer and storage). Note that additional image processing and analysis can be offered (including 3-D rendering and texture quantification) but are not included in the standard services.

Academic - NSERC
Academic - non-NSERC
Government/Industry
Data acquisition
$128 per hour $145 per hour $174 per hour
Data reconstruction
$18 per hour $23 per hour $28 per hour
Data processing (additional)
$38 per hour $48 per hour $58 per hour

An academic project is considered collaborative, including co-authorship on publications, if the data obtained in the XR-µCT lab are scientific contributions through study design and analysis. Additional 20% on the rates given above are charged for non-collaborative projects. Rates for large-scale projects can be negotiated. Free test scans (less than 1 hour scanning time) and pilot work can be offered to help determine whether XR-µCT may be beneficial to the research intended, and to assist in potential applications for project funding.