Brookhaven Lecture

To study how sound propagates through liquids, how biological molecules flop and perform their functions, and how seismic waves transmit through the center of the earth, scientists have used an experimental technique called inelastic x-ray scattering. The technique is made possible by bright synchrotron light sources that can be adjusted, or "tuned" to a particular wavelength. Currently, the technique is limited by the number of active instruments in the world and their need for improved energy resolution. The new National Synchrotron Light Source II (NSLS-II) to be built at BNL will provide the new impetus for the continuing growth of the technique in this country. In particular, one of the key goals of NSLS-II is to achieve 0.1meV energy resolution for inelastic x-ray scattering experiments, making it possible to explore a region of dynamical response, dubbed as "no man's land," which has never before been possible. Cai will review the current status of the inelastic x-ray scattering technique and research with examples taken from activities at BNL and elsewhere in the world. He will describe a new optical scheme that he and a team are investigating at NSLS-II, including research and development that promises to deliver the very high-resolution goal at only half the energy currently needed for much lower resolution results. As Cai will explain, this new capability is expected to provide the important link between viscous and elastic behaviors of disordered materials, and at the same time, create new opportunities for other areas of energy research for the future.