Journal Article X-ray optics Research Support, Non-U.S. Gov't Evaluation Study X-ray fluorescence X-ray free-electron laser X-ray free-electron lasers hard X-ray photoelectron spectroscopy intensity correlation Bragg diffraction HAXPES Published Erratum SACLA Validation Study X-ray beamline X-ray diffraction X-ray optical instruments X-ray refractive lenses XFEL beam divergence beamline development beamlines cavity-based X-ray free-electron lasers coherence data acquisition system diamond crystals diffraction-limited storage rings double multilayer monochromator double-crystal X-ray phase retarders energy calibration