Science frontier developed by x-ray free-electron laser

A Japanese X-ray Free-Electron Laser (XFEL) facility is under construction at SPring-8 in Hyogo prefecture as one of the key technologies of national importance and its completion is scheduled in spring 2011. This paper describes an outline of the XFEL facility and overviews its application feasibility to develop science frontier. A small prototype accelerator of the XFEL built for a proof-of-principle experiment has provided stable and intense Extremely Ultra-Violet (EUV) FEL for user experiments since May 2008. Science frontier being opened using EUV FEL is also introduced from the viewpoint to give readers clear image on science fields developed by the XFEL. (author)