Investigation of impurity motions with neutron resonance absorption method

用中子共振吸收法研究杂质运动

基本信息

批准号：
09440124
负责人：
IKEDA Susumu
金额：
$ 8.9万
依托单位：
High Energy Accelerator Research Organization
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

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.

强脉冲散裂中子源可以提供1-100 eV能量范围内的有用eV中子通量，并使中子共振吸收方法成为可能，许多重原子，如Au、Ag、Ta、U、Sb、Ba和Ho， (n,γ)反应在1-100eV能量范围内具有较大的中子吸收截面。通过测量吸收中子谱，可以大致知道。因此，这种新方法有望在杂质研究和无损检测等广泛的研究领域中发挥重要作用。在中子中实现了一种新型中子共振吸收光谱仪EZO。日本国家高能物理实验室的散射装置利用该光谱仪，成功测量了 Ta 原子有效温度 (TiiD2effieD2) 的角度依赖性和温度依赖性。我们还成功地分别测量了离子导体AgI中的Ag原子和I原子，发现Ag-的德拜温度T= 左右，原子从 T2D2effD2 = 160 K 变为 T2D2effD2 = 440 K 150 K，而 I 原子看不到任何变化。此外，该方法首次应用于硅半导体中杂质（包括杂质 Sb）的研究。 Si 半导体中的杂质 Sb 确定为 1.84x10D118D1 原子/cmD13D1，这非常吻合。 1.8x10D118D1 杂质Sb 与Sb 样品几乎相同。