question: Where is X-ray free electron laser used?
answer: X-ray free electron laser (XFEL) technologies provide coherent and extremely intense photon pulses of short duration. XFELs are particularly useful in structural biology and imaging, in structural studies of single biological macromolecules (e.g. high resolution protein structure determination) and assemblies (e.g. viruses) or nanocrystals, which are not amenable to investigation with traditional crystallographic methods. Moreover, XFELs have the potential to be used for studying enzyme kinetics.