Measurement of Anomalous Scattering Facotor near Absorption Edge by Pendellosung Beat

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The anomalous scattering factor in the actual crvstal differs from it of the theoretical calculation based on the free atom model near the absorption edge, which affects the bonding effect of the solid. Now, there is not enough to the experimental data. We found Pendellosung beat (PBXRS) caused by the change of the anomalous scattering factor and PBXRS is possible to determine accurately the anomalous scattering factor near the absorption edge. In the study, we measure PBXRS by the semi-conductor samples and wisker samples and obtained the anomalous scattering factor near the absorption edge. Moreover, we consider the result that compare the obtained one with one of the theoretical calculation.Before the experiment, we examined the diffraction condition by the dynamical theory included the absorption effect which can be observed PBXRS fine. The experiment performed to use the synchrotron radiation and the four-circle diffractometer with SSD set on BL6C1 in KEK-PF.Further, these used the measuring system and the small rotating diffractmeter (minimum set angle 0.02 sec.) set on phi axis of the fourcircle diffractometer. The samples were GaAs that is EPO within 500 cm^<-2> and processed on the parallel plate type. PBXRS of 200 reflection were measured by the energy steps of 0.42 eV near Ga K-absorption edge. The anomalous scattering factor obtained from the measured data by the profile fitting method. In this study, the real prat of the anomalous scattering factor of Ga (f'_<Ga>) is 2-6% smaller at 50 eV below the absorption edge and 9-13% smaller at 5 eV than ones of the theoretical calculation by Parratt and Hempstead's method and by Cromer and Liberman's method, respectively.