Tracking the Moves of Electrons

Improved x-ray techniques give scientists inside look at electron dynamics in superconductors, other advanced materials

EVENT: X-rays have long been used to study everything from the insides of the human body to the internal structure of proteins, computer chips, and batteries. At the U.S. Department of Energy’s Brookhaven National Laboratory, scientists are developing new ways to not only detect what’s in a material, but how those internal components — primarily, the electrons — move. Brookhaven physicist John Hill will discuss improvements being made to this technique — called inelastic x-ray scattering — as well as its impact on the study of superconductors, remarkable materials that conduct electricity with no resistance.

WHEN: Thursday, March 24, 2011, 2:30 p.m. Central Time

WHERE: March 2011 American Physical Society meeting, Dallas Convention Center, Dallas, TX, Room D161

BACKGROUND: Light sources around the world, including Brookhaven’s National Synchrotron Light Source (NSLS), use a technique called x-ray scattering to determine the internal structure of various materials. Typically, when an atom in a material is hit with an x-ray, it emits another one with the same energy. By measuring the angle of the expelled x-ray, scientists can determine the location of that atom. But sometimes, the emitted light is inelastic — it has slightly less energy than the incoming x-ray beam. This signals that the x-ray beam caused the sample’s electrons to hop from one atom to another. Scientists use inelastic x-ray scattering to measure this energy loss, which helps them determine how electrons behave in different samples. This technique is particularly important in the field of high-temperature superconductivity, where electrons pair up to carry electrical current with no resistance, or energy loss. If scientists can figure out how high-temperature superconductivity works, they might be able to develop practical materials for uses like more efficient power transmission lines. Now under construction at Brookhaven, the National Synchrotron Light Source II will produce x-rays 10,000 times brighter than those produced at NSLS. It also will include a dedicated inelastic x-ray scattering beamline, which will offer world-leading capabilities to scientists studying superconductors and a wide range of other materials.

This research is funded by the DOE Office of Science.

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