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Synchrotron radiation facilities are indispensable in numerous forefront areas. Until now, the electron energies of all photon sources in China have been in the medium- and low-energy regions. However, research related to national security and industrial innovation has demonstrated the urgent need for high-performance sources with high electron energy. For this purpose, a complex for advanced photon sciences in northern China has been planned since 2009 [1]. The complex is planned in three phases. In the first phase, a storage-ring-based, high-energy photon source (HEPS) with a beam energy of 5 GeV and emittance less than 1.0 nm•rad will be constructed, which can provide high-brilliance hard X-rays to several tens of experimental stations. In the second phase, a superconducting linac will be constructed to drive an X-ray free electron laser (XFEL), serving as an extension and compliment to the HEPS. In the third phase, as one possible performance upgrade scheme, the ring and the superconducting linac will...

Synchrotron radiation facilities are indispensable in numerous forefront areas. The existed photon sources in China are in medium and low energy region, however, the researches related to national important requirements and industrial innovation capabilities are in urgent need of high electron energy sources with high performance. To build a high energy synchrotron radiation facility with high performance in China would play important role in national security and industry areas and narrow the gap with internal sources and advanced light sources. In this paper, we described the necessity and signification to build high energy synchrotron radiation facility, analyzed the development of international synchrotron radiation facilities, mainly discussed the scientific objectives, preliminary proposal and technological challenges of High Energy Photon Source (HEPS), and systematically introduced the objectives and proposals of HEPS test facility, one of the scientific infrastructure development programs in the 12th Chinese five-year plan.

The coordination number of the gadolinium atom and bond distances in the crystal of monomeric porphyrinate, [Gd(TPP)acac·8H2O·3TCB] (TCB: 1,2,4-trichlorobenzene, acac: anion of acetylacetone), were determined by EXAFS method. The Gd atom is eight-coordinated to the four nitrogen atoms of a tetraphenylporphyrin ring, to the two oxygen atoms of one acetylacetonato anion and to two water molecules with Gd—N=0.232 nm, Gd—O=0.243 nm.

Sulfur K-edge X-ray absorption near-edge structure (XANES) spectroscopy was employed to study the speciation of sulfur in raw coal, ash by-product and fine particulate matter from a small coal-burning boiler. By means of least square analysis of the XANES spectra, the major organic and inorganic sulfur forms were quantitatively determined. The results show that about 70% of the sulfur in raw coal is present as organic and a minor fraction of the sulfur occurs as other forms: 17% of pyrite and 13% of sulfate. While in bottom ash, fly ash, and PM(2.5), the dominant form of sulfur is sulfate, with the percentage of 80,79 and 94, respectively. Moreover, a number of other reduced sulfur including thiophenic sulfur, element sulfur and pyrrhotite are also present. During coal combustion, most of organic sulfur and pyrite were oxidized and released into the atmosphere as SO(2) gas, part of them was converted to sulfate existing in coal combustion by-products, and a small part of pyrite was probably reduced to elemental sulfur and pyrrhotite. The results may provide information for assessing the pollution caused by small boiler and developing new methods for the control of SO(2) pollution.

X-ray absorption fine structure (XAFS) spectroscopy is a powerful technique for the investigation of the local environment around selected atoms in condensed matter. XAFS under pressure is an important method for the synchrotron source. We design a cell for a high pressure XAFS experiment. Sintered boron carbide is used as the anvils of this high pressure cell in order to obtain a full XAFS spectrum free from diffraction peaks. In addition, a hydraulic pump was adopted to make in-suit pressure modulation. High quality XAFS spectra of ZrH2 under high pressure (up to 13 GPa) were obtained by this cell.

In this paper, we investigate the crystalline and electronic structure of Ni nanoclusters supported on Al2O3 and Cr2O3 obtained at different reduction temperatures. Their physical properties were characterized by powder X-ray diffraction, X-ray absorption spectroscopy and X-ray photoelectron spectroscopy techniques. The global parameters of the active metal nanostructure such as average crystallite size and the microstrain are obtained by the generalized Fermi function for fitting the experimental X-ray line profiles. By X-ray absorption spectroscopy we evidenced a diminution of the coordination number in the first shell of the nickel atoms. In order to characterize the electronic structure of the active metal, X-ray photoelectron spectroscopy measurements were performed. Our results give additional information about the strong interaction between the metal clusters and oxide supports.

In a previous paper a study of the supported nickel catalysts based on extended X-ray absorption fine structure spectroscopy was presented for analysis of the first coordination shell. The present study evidenced a strong deformation of the local structure of the metal due to its interaction with oxide support. The average particle size, microstrains and probability of faults, the particle size distribution function of supported Ni catalysts were determined by X-ray diffraction method. The method is based on Fourier analysis of experimental X-ray line profile (1 1 1), (2 0 0) and (2 2 0). The global structure is obtained with a fitting method based on the generalized Fermi function facilities for approximation. A chemisorption model was elaborated by correlation of the local and global structure connected with the specific surface areas. The results obtained on supported Ni catalysts which are used in H/D isotopic exchange reactions are reported. Both types of measurements were performed on the Beijing synchrotron radiation facilities.

The in vivo coordination structure of lanthanum ions interacting with chlorophyll-a of the fern Dicranopteris dichotoma grown in a rare earth minefield in southern China was determined by the extended x-ray absorption fine structure (EXAFS). The results show that lanthanum includes two porphyrin rings in its coordination sphere. It is postulated that the La-chlorophyll-a complex may have a bilayer structure. The analytical method may serve as a new tool to gain insight in the in vivo interactions of rare earth elements.

High solid-solubility Co15Cu85 alloys were prepared by melt spining and then submitted to isothermal and anisothermal annealing to obtain granular alloys. The synchrotron radiation x-ray diffraction patterns and extended x-ray absorption fine structure (EXAFS) spectra were measured to investigate the decomposition of supersaturated solid solution upon annealing. Experimental results indicated the precipitation of ultrafine Co-rich particles occurred at about 500°C and the annealing had a great influence on the middle-range order of Co atoms. While the fitted EXAFS spectra showed that the interfaces of Co precipitates seem to be enriched with vacancy-type defects, leading to distorted interfaces.

We discover a pressure induced quantum phase transition from the superconducting state to the non-superconducting Kondo screened phase associated with a 2% volume collapse in CeFeAsO0.7F0.3 through measurements of high-pressure resistance, synchrotron x-ray diffraction, and x-ray absorption spectroscopy (XAS) in a diamond anvil cell. Our XAS data of Ce-L3 in CeFeAsO0.7F0.3 clearly show a spectral weight transfer from the main line to the satellite line after the transition, demonstrating the formation of the Kondo singlets under pressure in CeFeAsO1-xFx. Our results have revealed a physical picture of a pressure-induce competition between Kondo singlets and BCS singlets in the Ce-pnictide superconductors., Comment: 18 pages, 5 figures

The structure of the extraction complexes of light lanthanides (La(III), Nd(III), Eu(III)) with bis(2,4,4-trimethylpentyl)dithiophosphinic acid (HBTMPDTP) have been characterized with extended X-ray absorption fine structure spectroscopy (EXAFS), IR, and MS; the IR spectrum of the extraction complex of (241)Am with HBTMPDTP has been studied too. The molecular formula of the extraction complexes of lanthanides is deduced to be HML(4).H(2)O (M = La, Nd, Eu; L = anion of HBTMPDTP). The coordination number of Ln(III) in the complexes is 8; the coordinated donor atoms are 7 sulfur atoms from 4 HBTMDTP molecules and 1 O atom from a hydrated water molecule. With the increase of the atomic number of Ln, the coordination bond lengths of Ln-O and Ln-S decrease in the complexes. For La(III), Nd(III), and Eu(III), the coordination bond lengths of Ln-O are 2.70, 2.56, and 2.50, respectively, the coordination bond lengths of Ln-S are 3.01, 2.91, and 2.84, respectively, and the average distances between Ln and P atoms are 3.60, 3.53, and 3.46, respectively. The structure of the extraction complexes of Ln(III) with HBTMDTP is different from that of the Am(III) extraction complex. The results of IR show that there is no water coordinated with Am in the extraction complex. The molecular formula of the complex of Am(III) is deduced as being HAmL(4), and there are 8 S atoms from 4 HBTMPDTP molecules coordinated with Am. Composition and structure differences of the extraction complexes may be one of the most most important factors affecting the excellent selectivity of HBTMPDTP for Am(III) over Ln(III).

The foundation of the first synchrotron radiation x-ray absorption fine structure (XAFS) station in China has been completed and the station was ready for transmission XAFS experiment. This paper reports the first XAFS spectrum recorded in this station and the result of performance test centered on the intensity, energy dispersion and energy accuracy of the beam line in this station.

The present work is a comparison study between different algorithms of Fourier transform for obtaining very accurate local structure results using Extended X-ray Absorption Fine Structure technique. In this paper we focus on the local structural characteristics of supported nickel catalysts and Fe3O4 core-shell nanocomposites. The radial distribution function could be efficiently calculated by the fast Fourier transform when the coordination shells are well separated while the Filon quadrature gave remarkable results for close-shell coordination.

Diffraction enhanced imaging (DEI) with two crystals has been recently performed at the 4W1A beamline at the Beijing Synchrotron Radiation Facility (BSRF). In the first experiments, images collected with a set up where the rotation axis of the crystal was perpendieular to the orbit, show a higher quality with respect to those taken with a geometry with the rotation axis of the monochromatic crystal parallel to the orbit. When the rotation axis of the crystal is perpendicular to the orbit plane, e.g. to the polarization plane of the synchrotron radiation, the influence of both vibration and thermal expansion of the first crystal can be significantly reduced, allowing the collection of better images. In this work, a systematic comparison is male between two geometrical arrangements of crystals in DEI framework with respect to the reflectivity of crystals, spacial resolution, angular resolution and image contrast.

Diffraction_enhanced imaging by using two crystals has been recently developed i n x_ray topogrphy station in Beijing Synchrotron Radiation Facility. In this art icle the analysis for the influence of the thermal expansion of the first crysta l on the diffraction enhanced imaging is presented. The conclusion is that the i nfluence of the thermal expansion of the first crystal can be avoided and much b etter images can be obtained when the axes of crystals are placed vertically to the polarization plane of the synchrotron radiation. The experimental results co nfirmed this analysis.

The conventional holography met with three unsolvable difficulties,such as coherence of light source,spatial resolution and sensitivity of detector,when applied in atomic imaging. This paper is intended to explain how the inside source holography can overcome all these difficulties,and to investigate the recording and reconstruction procedures of the inside source holography. The reconstruction formula of inside source spherical hologram and the δ-functions describing reconstructed atomic images in spherical-symmetrical and energy-irrelevent approximations of atomic scattering factor are deduced

The EXAFS technique was used to study the changes of Fe and Cu atom neighbor environment following the milling time and composition of Fe-Cu system. The resutls show that the range of Fe-Cu solid solution can be greatly extended and can form nanometer sized non-equilibrium metastable alloy particles mechanical alloying. For Ｆｅ 80 Ｃｕ 20 (160h), K-edge absorption curve and radial structure function of Cu are similar to that of a-Fe powder, has the bcc structural characte-ristics, the Fe-Cu alloy particles is bcc structure also. The structure of Fe-Cu alloy in Ｆｅ 60 Ｃｕ 40 (160h) is the fcc structure, it is different from that of Ｆｅ 80 Ｃｕ 20 (160h). In nanometer sized Fe-Cu metastable alloy particles of Ｆｅ 60 Ｃｕ 40 (160h), Cu and Fe are not uniformly dispersed, Cu is a little richer in the core, but Fe is abundant on the surface.