Measurements of differential cross section for x-ray diffraction in amorphous materials using synchrotron radiation

摘要

Two effects should be considered when keV photons suffer elastic scattering: the scattering of photons by the bound electrons of a free atom, named Rayleigh scattering and if, besides the Rayleigh scattering, the scattering due to different atoms gives rise to interference phenomena. The interatomic and intermolecular co-operative effects which modify the free-atom coherent scattering process are well known for highly ordered structures such as crystalline materials but are important for amorphous solids and liquids where short-range ordering occurs. Amorphous materials (lacking in well-defined crystalline structure) do not give such well-defined scatter conditions, but they do still give diffraction patterns which is characteristic of the particular material. The availability of a very intense and highly collimated synchrotron radiation beam makes possible to study scattering properties of different amorphous materials (water, lucite, nylon, polystyrene and hydroxyapatite). These materials were chosen because they intend to simulate the physical properties of body tissues and human bone. All measurements were performed at the X-ray Diffration Beamline of the Laboratorio Nacional de Luz Sincrotron (LNLS), in Campinas, Brazil. The X-ray diffraction measurements were carried out with an 11.101 keV (λ = 1.117A) X-ray beam and included data from q = 0.39 to q = 4.13 per nm.