Spherically Bent Crystal Analyzers (SBCAs) are the core optical components of x-ray spectrometers. They have been widely used in many x-ray spectroscopy end-stations at synchrotron radiation and x-ray free electron laser facilities around the world. Owing to the monochromatic and focal properties of SBCAs, x-ray spectrometers with high efficiency and high energy resolution can be well applied to the study of x-ray absorption spectroscopy (XAS) and emission spectroscopy (XES). Hence, the quality of SBCAs is the key factor in determining the performance of x-ray spectrometers. Previously, we have investigated the focal properties of Si(444) SBCAs by using a laboratory’s Rowland circle device. However, the original device is limited by movement distance of motors and the space between detector and x-ray source. It is only applicable to SBCAs with a radius of curvature of 500 mm, and the maximum Bragg angle is 86°. Here, we present a new simple near backscattering detection device, which is based on a long linear guideway, to inspect the surface morphology, crystal face morphology, and focal performance of SBCAs at Bragg angle of 88°. By simply adjusting the distance between the source, SBCAs, and detector, focal performance at the focal point can be detected, while crystal face can be imaged off the focal point. By switching the x-ray source to the LED light source, surface morphology is able to be imaged as well. Furthermore, SBCAs with different radius of curvatures within 1000 mm are all measurable by this new device.
Transient structural information of matter can be obtained by time-resolved X-ray measurement, such as ultrafast X-ray diffraction (UXRD) and ultrafast X-ray absorption Spectroscopy (UXAS). A time-resolved ultrafast X-ray source is necessary for ultrafast X-ray spectroscopy measurements, such as XFEL or synchrotron radiation source. Because of the high cost of X-ray free electron laser (XFEL) and synchrotron radiation source, we designed a laboratory ultrafast plasma X-ray source driven by 800Hz high-energy laser. The X-ray pulse duration is shorter than 100fs. Copper was chosen as the target material of the source, and the expected photon flux can reach 107 photons/s. The target material can also be replaced by other common target materials.
X-ray spectroscopy is an important technique for studying the material electronic structure, oxidation state and coordination, which have wide applications in energy catalysis, environmental science fields. The crystals diffract X-rays because their internal atoms are spatially ordered and the lattice spacing is on the nanometer scale, which is similar to the X-ray wavelength. In this paper, a technique based on bending and epoxy adhesive is proposed to fabricate a bent crystal analyzer. The radius of convex surface is 1‰ smaller than the concave one. The wafers and spherical substrates were cleaned with acetone and ethanol in an ultra-clean room. To remove residual organic compounds, UV ozone cleaning procedure should be used. The results show that the measured curvature radius of the bent crystal analyzer is 1000.550 mm; the surface RMS of the surface is 1.34λ and the energy resolution is better than 5 eV, which can distinguish Cu Kα1 and Kα2 fluorescence lines.
A time-resolved soft X-ray emission spectrometer covering 250-620 eV is presented for the study of chemical reaction processes. Contrary to conventional time-resolved spectrometer, our spectrometer can obtain a two-dimensional timeenergy map in single shot by adding an imaging mirror to the flat-field spectrometer. The temporal changes are spatially encoded in the footprint of the probe X-ray beam on the sample via grazing incidence geometry. The flat-field spectrometer design is chosen to alleviate the aberration of the imaging mirror. The spectrometer is optimized at 400 eV, targeting at over 2000 resolving power and sub-picosecond time resolution.
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