The chemistry inside

摘要

One of the most striking properties of X-rays is their ability to penetrate matter. In fact, X-rays are partially absorbed as they pass through an object, and cast a 'shadow' of the structures inside - an effect that underpins medical X-ray imaging. As objects become bigger, harder (more energetic) X-rays are needed to penetrate them. The problem is that the harder the X-rays, the smaller the imaging contrast for light elements - those that have low relative atomic masses, such as carbon, nitrogen and oxygen. Reporting in Nature Materials, Huotari et al.' now describe a way of using hard X-rays to make three-dimensional images of objects that also detects light elements with high sensitivity. The technique even distinguishes between different bonding modes of those elements, and should enable studies of the interiors of diverse objects, such as biological systems, working catalytic reactors and fuel cells.