Single-grating Talbot imaging relies on high-spatial-resolution detectors to perform accurate measurements of X-ray beam wavefronts. The wavefront can be retrieved with a single image, and a typical measurement and data analysis can be performed in few seconds. These qualities make it an ideal tool for synchrotron beamline diagnostics and in-situ metrology. The wavefront measurement can be used both to obtain a phase contrast image of an object and to characterize an X-ray beam. In this work, we explore the concept in two cases: at-wavelength metrology of 2D parabolic beryllium lenses and a wavefront sensor using a diamond crystal beam splitter.
We report on the manufacturing and X-ray tests of bent diamond-crystal X-ray spectrographs, designed for
noninvasive diagnostics of the X-ray free-electron laser (XFEL) spectra in the spectral range from 5 to 15 keV.
The key component is a curved, 20-μm thin, single crystalline diamond triangular plate in the (110) orientation.
The radius of curvature can be varied between R = 0:6 m and R = 0:1 m in a controlled fashion, ensuring
imaging in a spectral window of up to 60 eV for ~ 8 keV X-rays. All of the components of the bending
mechanism (about 10 parts) are manufactured from diamond, thus ensuring safe operations in intense XFEL
beams. The spectrograph is transparent to 88% for 5-keV photons, and to 98% for 15-keV photons. Therefore,
it can be used for noninvasive diagnostics of the X-ray spectra during XFEL operations.