High energy synchrotron X-ray diffraction study of lead oxide silicate glasses at the Canadian light source

摘要

The photon energy operational range of the hard X-ray micro-analysis (HXMA) beamline with X-ray produced from a superconductivity wiggler at the Canadian Light Source is extended to 50 keV to investigate the feasibility of performing total diffraction experiments. Diffraction patterns of lead oxide silicate glasses (Pb0_xSi0_2(1-x)) x=46, 50 and 61 at% were measured. Structures of the glasses were extracted successfully from Fourier transform of the diffraction patterns. It is shown that the extended q range (q_max = 14.2 A"1) leads to radial distribution functions (RDFs) with sufficient resolution (0.44 A) to reveal new coordination features. The advantage of high momentum transfer accessible from hard X-ray is clearly demonstrated. Results show that the lead atoms are surrounded by three oxygen and the derived Pb-O-Pb angle ca. 109° supports the existence of -O-(Pb_2O_2)-O units in the glass structure, which illustrates the capability of the new beamline for the investigation of the structure of disordered solids.