Seminars Archive

Single molecules in the beam of the LCLS

Abstract
Theory predicts that with an ultra-short and extremely bright coherent X-ray pulse, a single diffraction pattern may be recorded from a large macromolecule, a virus, or a cell before the sample explodes and turns into a plasma. The over-sampled diffraction pattern permits phase retrieval and hence structure determination. The first free-electron lasers (FELs) capable to deliver ultra bright and very short X-ray pulses for such experiments have recently started operations. These are the most bri lliant sources of X-rays to date, exceeding the peak bri lliance of conventional synchrotrons by nearly 10 billion times, and improving. In the duration of a single flash, the beam focused to a micron-sized spot has the same power density as all the sunlight hitting the Earth, focused to a millimetre square. The talk will summarise experiments on single virus particles and single macromolecules.