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.
Ultra-thin (< 100 um) diamond single crystals are essential for the realization of numerous next generation x-ray optical devices. Fabrication and handling of such ultra-thin crystal components without introducing damage and strain is a challenge. Drumhead crystals, monolithic crystal structures comprised of a thin membrane furnished with a surrounding solid collar would be a solution for the proper handling ensuring mechanically stable and strain-free mount of the membranes with efficient thermal transport. However, diamond being one of the hardest and chemically inert materials poses insurmountable difficulties in the fabrication. Here we report on a successful manufacturing of the diamond drumhead crystals using picosecond laser milling. Subsequent temperature treatment appears to be crucial for the membranes to become defect-free and unstrained, as revealed by x-ray double-crystal topography on an example of drumhead crystals with 1-mm in diameter and 28 um to 47 um-thick membranes in the (100) orientation.
We demonstrate parabolic single-crystal diamond compound refractive
lenses  designed for coherent x-ray imaging
resilient to extreme thermal and radiation loading expected from
next generation light sources. To ensure the preservation of
coherence and resilience, the lenses are manufactured from the highest-quality
single-crystalline synthetic diamond material grown by a high-pressure
high-temperature technique. Picosecond laser milling is
applied to machine lenses to parabolic shapes with a ~1-micron
precision and surface roughness. A compound refractive lens
comprised of six lenses with a radius of curvature R=200 microns at
the vertex of the parabola and a geometrical aperture A=900 microns
focuses 10~keV x-ray photons from an undulator source at the Advanced
Photon Source facility to a focal spot size of ~ 10x40 microns^2 with a gain factor of ~100.\\
 S. Terentyev, V. Blank, S. Polyakov, S. Zholudev, A. Snigirev, M. Polikarpov, T. Kolodziej, J. Qian,
H. Zhou, and Yu. Shvyd'ko Applied Physics Letters 107, 111108 (2015); doi: 10.1063/1.4931357
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.