X-ray emission from metal oxide crystals under dynamical electron diffraction conditions and its application to structure analysis

This project aimed for a new method of structural analysis on local areas in disordered metal oxidecrystals, such as irradiated MgO, Al2O3 and MgO Al2O3，promoting a better understanding on the interactions of dynamical elastic scattering of incidentelectrons with inelastic scattering process generating characteristic x-rays.The project researchstarted in 1997 with examination on the atomic scattering factors of Mg - D1+ O - 12- d - D1，through the measurement of critical voltage for 400 flection of MgO by high voltage electrondiffraction. The measured value of critical voltage 826±3kv is in quite good agreement with基于原子分选因子fs和B-factors recently obtained byRez et al. And Zuo. It was therefore concluded that their values of f And B are reliable inquantitative analysis of dynamical electron scattering in MgO and相关ceramic compounds.In the1998年，the electron channeling enhanced x-ray microanalysis an…More d the large angle convergent beam electron diffraction simultaneously employed tonAl2O3 crystals as a function of n and irradiation does with 1 nAl2O3 crystals as a function of n and irradiation does with 1MeV electrons or 300kev O - ions. The cation distribution is hardly changed under与1 MeV electrons to 1.9 dpa at 870K. On contrast significant displacements ofcations are induced under irradiation with O ions to 1.4 dpa at the same temperature.In the1999年final year我们examined high angular resolution electron channeling x-ray spectroscopy (HARECXS) as a procticaltool to locate lattice ions in spinel compounds. The orientation dependent intensity distribution ofemitted x-rays obtained by HARECXS so sensitive to ion configuration as to determine theoccupation probabilities on specific sites in the crystal lattice accurately. HARECXS has revealedpartially disordered cation arrangement in Mgo nAl2O3 irradiated with 1 MeV Ne ions as afunction of depth from the irradiated surface. Less

This project aimed for a new method of structural analysis on local areas in disordered metal oxide crystals, such as irradiated MgO, Al2O3 and MgO・Al2O3, promoting a better understanding on the interactions of dynamical elastic scattering of incident electrons with inelastic scattering process generating characteristic x-rays.The project research started in 1997 with examination on the atomic scattering factors of MgィイD1+ィエD1 and OィイD12-ィエD1, through the measurement of critical voltage for 400 reflection of MgO by high voltage electron diffraction. The measured value of critical voltage 826 ± 3 kV is in quite good agreement with estimation based on the values of atomic scattering factors fs and B-factors recently obtained by Rez et al. And Zuo. It was therefore concluded that their values of f and B are reliable in quantitative analysis of dynamical electron scattering in MgO and related ceramic compounds.In the second year 1998, the electron channeling enhanced x-ray microanalysis an … More d the large angle convergent beam electron diffraction were simultaneously employed to determine cation configuration in Mgo・nAl2O3 crystals as a function of n and irradiation does with 1 MeV electrons or 300 KeV OィイD1+ィエD1 ions. The cation distribution is hardly changed under irradiation with 1 MeV electrons to 1.9 dpa at 870K. On contrast significant displacements of cations are induced under irradiation with OィイD1+ィエD1 ions to 1.4 dpa at the same temperature.In the final year 1999, we examined high angular resolution electron channeling x-ray spectroscopy (HARECXS) as a proctical tool to locate lattice ions in spinel compounds. The orientation dependent intensity distribution of emitted x-rays obtained by HARECXS is so sensitive to ion configuration as to determine the occupation probabilities on specific sites in the crystal lattice accurately. HARECXS has revealed partially disordered cation arrangement in Mgo・nAl2O3 irradiated with 1 MeV NeィイD1+ィエD1 ions as a function of depth from the irradiated surface. Less