Scientific Opportunities at Free Electron Laser (FEL) Sources
Dr. Gerhard Gruebel (Hasylab/DESY)

The scientific opportunities at fourth generation light sources such as the Euro-pean XFEL Facility (XFEL) in Hamburg or the Linac Coherent Light Source (LCLS) in Stanford are truly revolutionary since their key properties such as bril-liance, spatial coherence and time structure are many orders of magnitude more favorable compared to the best storage ring based synchrotron radiation sources today. For the first time it will become possible to study matter on atomic length and time scales, i.e. with resolution of 0.1 nm in space and femto-seconds in time. This will eventually allow one to probe the time evolution of solid-state structures and chemical reactions on the femto-seconds timescale and/or to solve the structure of biomolecular systems without the need for crystallization. One will be able to explore the non-linear properties of matter in the X-ray range and the dynamics of fluctuations on interatomic length and time scales. Further-more it will be possible to produce and investigate matter in portions of its phase diagram inaccessible to other probes.