Journal Article X-ray optics Bragg diffraction X-rays diamond crystals Bragg reflectivity Research Support, U.S. Gov't, Non-P.H.S. X-ray Bragg diffraction X-ray focusing X-ray free-electron laser X-ray free-electron laser oscillators X-ray free-electron lasers X-ray refractive lenses at-wavelength metrology cavity-based X-ray free-electron lasers coded mask crystal diffraction diamond crystals diamond monochromators diffraction gratings electron-energy jitter free-electron lasers hard X-rays inelastic X-ray scattering phase error radiation damage refractive lenses self-amplified spontaneous emission self-seeding