Research and developments

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MICRO-CT for SEM

Using an electron beam in a scanning electron microscope (SEM) to generate x-rays allows the enhancement of standard SEM surface imaging to 2D and 3D x-ray projection imaging of objects. Our recent results have demonstrated a 3D micro-CT resolution better than 1µm, to be achievable by using an inexpensive attachment to any standard SEM.

Left to right: a standard SEM image in SE mode, an x-ray projection image, a full 3D-reconstruction, and a coronal section, obtained non-invasively by an x-ray attachment to SEM from a Ni-foam sample with 5µm thick walls.

ELEMENTAL MICRO-CT

To date, no CT or micro-CT scanner has been able to provide any 3D information about local chemical composition inside a sample. Using a state-of-the-art depth cooled array detector in energy-selective photon counting mode, SkyScan has combined micro-CT and X-Ray Fluorescence (XRF) to obtain 3D compositional maps. A specially developed x-ray camera for compositional imaging collects 2D elemental maps of the sample, and subsequent CT scanning produces virtual slices through the sample onto which maps of spatial distribution of chemical elements can be overlaid. This opens the exciting possibility of adding 3D elemental information to conventional micro-CT results.

Projection images (top) and reconstructed sections (bottom) from a bundle of foils and wires of different materials; an x-ray absorption image (left), an elemental map (middle) and the combined image (right).