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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.

强脉冲散裂中子源能提供1 ~ 100 eV的有效中子通量，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，在1 ~ 100 eV的特征能量范围内具有较大的（n, γ）反应中子吸收截面。通过测量中子吸收谱，一般可以知道样品中原子核的种类和运动。因此，这种新方法在杂质研究和无损检测等广泛的研究领域有很大的应用前景。在日本国家高能物理实验室的中子散射装置上实现了一种新型中子共振吸收光谱仪EZO。谱仪,我们成功地测量角依赖有效的温度和温度的依赖关系(TィイD2effィエD2)的Ta-atom层复合TaS2,和讨论部分声子密度TaS2 Ta-atom状态。我们还成功地分别测量了离子导体AgI中ag原子和i原子的德贝温度，发现ag原子的德贝温度在T= 150 K左右从T= 160 K变化到T= 440 K，而i原子没有变化。此外，该方法还首次应用于硅半导体中杂质（包括杂质Sb）的研究。在这项工作中，测定了si半导体中杂质Sb的浓度为1.84 × 10 μ c /cm μ c / D13 μ c / D1。这与化学分析的结果很吻合。1.8 × 10 × 118 × 1。TィイD2effィエD2的杂质某人是Sb-sample的几乎相同的。