Researchers get fired up for x-ray free-electron lasers

Nature News : A new generation of light sources—the newly completed Linac Coherent Light Source (LCLS) at the SLAC National Accelerator Laboratory in Menlo Park, California; one under construction in Japan ; and the European X-Ray Free-Electron Laser (XFEL) being built at DESY in Germany—are getting set not only to put atoms and molecules under the spotlight, but also to illuminate their dynamics.The devices, called x-ray free-electron lasers , produce flashes of x-ray light with angstrom -level wavelengths—small and coherent enough to image individual atoms. The flashes are also more intense than any created before—stuffed with enough photons to create and study extreme states of matter such as plasma.But perhaps most importantly, the bursts of light are short—just hundreds of femtoseconds long, the time it takes for light to cross a human hair. Pulses as brief as this can record functions, not just forms: the folding of a protein, the action of a catalyst, the splitting of a chemical bond.