Journal Article free-electron laser FLASH Research Support, Non-U.S. Gov't SASE XUV Raman spectrometer photon pulse duration Kirkpatrick–Baez mirror system Kirkpatrick–Baez mirrors NOM Research Support, U.S. Gov't, Non-P.H.S. X-ray optics alignment diffraction diffraction gratings electron-ion-spectrometers extreme ultraviolet radiation free-electron lasers high repetition rate diagnostics imaging detector interferometry line scan camera linear array detector metrology for synchrotron optics micro-focus microfocus monochromators multi-color lasing multiplex photoionization