Investigation of impurity motions with neutron resonance absorption method

Intense pulsed spallation neutron sources can provide a useful eV neutron flux in the energy range1-100 eV，and made a neutron resonance absorption method possible.Many heavy atoms，such as Au，Ag，Ta，U，Sb，Ba and Ho，have large neutron absorption cross-sections of(n，γ)reaction at the characteristic energies in the energy range1-100 eV。By measuring the neutron spectrum of absorption，one can generally know the kind of nucleus and the motion in samples。Therefore，it has been expected that this new method become very useful in the wide research field such as impurity researches and non-destructive inspection.A new neutron resonance absorption spectrometer EZO was realized in the neutron scattering facility in National Laboratory for High Energy Physics，Japan。With this spectrometer，we succeeded to measure both the angular dependence and temperature dependence of effective temperatures(T I D2)of Ta-atom in the layer compound TaS2，and to discuss the partial phonon desity of states of Ta-atom in TaS2.We also succeeded to measure T y D2eff D2‘s of Ag-atom and I-atom in an ionic conductor AgI，respectively and found at the measure Tey D2eff D.Further，this method were，for the first time，applied on the study of impurity in a si-semiconductor(Including Impurity Sb)。In this work，the concentration of the impurity Sb in the Si-semiconductor was determined to be 1.84x10 I D 118 I D 1 atoms/cm I D 13 I D 1.This is in good agreement to the result of the chemical analysis.1.8 x 10 I D 118 I D 1.The T I D 2 eff D 2 of the impurity Sb was almost identical to that of the Sb-sample。

Intense pulsed spallation neutron sources can provide a useful eV neutron flux in the energy range 1-100 eV, and made a neutron resonance absorption method possible. Many heavy atoms, such as Au, Ag, Ta, U, Sb, Ba and Ho, have large neutron absorption cross-sections of (n, γ) reaction at the characteristic energies in the energy range 1 - 100 eV. By measuring the neutron spectrum of absorption, one can generally know the kind of nucleus and the motion in samples. Therefore, it has been expected that this new method become very useful in the wide research field such as impurity researches and non-destructive inspection.A new neutron resonance absorption spectrometer EZO was realized in the neutron scattering facility in National Laboratory for High Energy Physics, Japan. With this spectrometer, we succeeded to measure both the angular dependence and temperature dependence of effective temperatures (TィイD2effィエD2) of Ta-atom in the layer compound TaS2, and to discuss the partial phonon desity of states of Ta-atom in TaS2.We also succeeded to measure TィイD2effィエD2's of Ag-atom and I-atom in an ionic conductor AgI, respectively, and found that the Debye temperature of Ag-atom changes from TィイD2effィエD2 = 160 K to TィイD2effィエD2 = 440 K around T= 150 K, while any change cannot be seen for I-atom. Further, this method were, for the first time, applied on the study of impurity in a si-semiconductor (including impurity Sb). In this work, the concentration of the impurity Sb in the Si-semiconductor was determined to be 1.84x10ィイD118ィエD1 atoms/cmィイD13ィエD1. This is in good agreement to the result of the chemical analysis. 1.8x10ィイD118ィエD1. The TィイD2effィエD2 of the impurity Sb was almost identical to that of the Sb-sample.