The design of the user station for a fourth-generation synchrotron radiation (SR) source SRF “SKIF” has been proposed. The station is designed to solve a wide range of research and technological tasks using X-ray diffraction techniques. The concept of the station is based on the implementation of a complex approach to the structural studies of synthetic and natural objects. The most complete set of experimental diffraction techniques will allow one to benefit from the unique advantages of a modern SR source, including advanced X-ray optic solutions, high SR brightness and efficient X-ray detectors.
Superconducting undulator with a magnetic period of 15.6 mm, an interpolar gap of 8 mm and a total length of 2 m will be used as insertion device (ID). In the main mode the magnetic field in the undulator will be 1.06 T (K = 1.54) giving SR harmonics generation with a step of 2.5 keV. The station includes four sections: High-resolution powder diffraction (section 1-2-1); In situ diffraction (section 1-2-2); Single-crystal X-ray diffraction (section 1-2-3); Small angle X-ray scattering (section 1-2-4). In the main operating mode of the ID all the sections are supposed to work simultaneously. This is achieved by splitting the components of the SR spectrum between different sections by three beam multiplexing monochromators (beam splitters). Flat diamond plates with an (111) orientation and a thickness of about 100 μm will be used to split the beam. The components of ID spectrum with energies of 12.50 keV / 0, 99 Å, 22.50 keV / 0.55 Å and 32.50 keV / 0.38 Å will be directed to side sections of the station at angles of 28, 15 and 11° with respect to primary beam. For the experiments requiring energy scanning an alternative mode will be used provided by the possibility of the change of the magnetic field in the undulator. In this mode the undulator radiation transmitted to only 1-2-1 section due to the restrictions of the multibranch optical design. To obtain the necessary beam parameters we plan to use the refractive X-ray optics beryllium, diamond or aluminum lenses depending on beam energy. To detect diffraction pattern, we propose to use modern hybrid-type detectors based on sensors made of silicon or cadmium telluride for high energy applications.
The work was supported by Ministry of Science and Higher Education of the Russian Federation (grant No. АААА-А19-119020890025-3).