New NIST imaging tool has X-ray eyes

Researchers at the National Institute of Standards and Technology have developed a new way of seeing—with X-ray “eyes” no less. Using its novel instrument, the NIST team can clearly glimpse minute voids, tiny cracks and other sometimes indiscernible microstructural details over a three-dimensional expanse in a wide range of materials, including metals, ceramics and biological specimens.

In its current form, the technology—called ultra-small-angle X-ray scattering or USAXS imaging—functions much like a film camera, albeit a highly specialized one. And where a camera needs a flash to create images, USAXS has the ultimate flash—the Advanced Photon Source at the Argonne National Laboratory. Measuring 1,104 meters (nearly 0.7 mile) around, the APS is a new-generation synchrotron. It produces an abundance of extremely uniform high-energy X-rays that make the new imaging technique work.

USAXS itself is an already established research technique, yielding plots of data points that correspond to angles and intensities of X-rays scattered by a specimen. With the new system, graphed curves become high-resolution pictures. And when taken from different perspectives, pictures can be assembled into three-dimensional images.

Images are actually maps of the small fraction of X-rays that—instead of being absorbed or transmitted through the sample—are scattered by electrons in the material.