Systematic Study on Fast-Neutron Capture Cross Sections of Stable Isotopes related Long-Lived Fission Products

稳定同位素相关长寿命裂变产物快中子俘获截面的系统研究

基本信息

批准号：
15360502
负责人：
IGASHIRA Masayuki
金额：
$ 9.47万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15360502/
关键词：
fast-neutron reaction capture cross sections capture gamma-ray spectra zirconium isotopes tin isotopes long-lived fission products 超寿命核分裂生成物

项目摘要

The main objectives of this study are (1)improvemant in the sensitivity of gamma-ray detection system, (2)systematic measurement of fast-neutron capture cross sections and capture gamma-ray spectra for Zr-90,91,92,94 and Sn-117,118,119,120,122,124, which are impurity isotopes of the long-lived fission products Zr-93 and Sn-126, respectively, (3)improvemant in accuracy of theoretical prediction by the elucidation of fast-neutron capture reaction mechanism for Zr and Sn isotopes through the systematic analysis of experimental data, and (4)accurate evaluation of fast-neutron capture cross sections of the long-lived fission products Zr-93 and Sn-126. The summary of research results are as follows :(1) The existing main NaI(Tl) detector was replaced with a larger NaI(Tl) detector with a diameter of 15 cm and a length of 30 cm, and the sensitivity of gamma-ray detector was improved.(2) The systematic measurement was performed for Zr-90,91,92,94 and Sn-116,117,118,119,120,122,124. The data processing was completed for Zr-90,91,92,94 and Sn-117,118,119, and the capture cross sections and capture gamma-ray spectra were derived for those isotopes.(3) The derived capture cross sections and capture gamma-ray spectra of Zr-90,91,92,94 and Sn-117,118,119 were theoretically analyzed by using the statistical model in nuclear reaction theory, and information on the fast-neutron capture reaction by Zr and Sn isotopes was obtained.(4) The evaluation of fast-neutron capture cross sections of the long-lived fission products Zr-93 and Sn-126 was performed based on the obtained information, and evaluated values were obtained tentatively.

本研究的主要目的是（1）提高伽马射线探测系统的灵敏度，（2）系统测量Zr-90、91、92、94和Sn-117,118,119,120,122,124，是长寿命裂变产物Zr-93和Zr-93的杂质同位素Sn-126分别通过系统分析实验数据，阐明Zr和Sn同位素的快中子俘获反应机理，提高理论预测的准确性；(4)准确评估快中子俘获交叉长寿命裂变产物 Zr-93 和 Sn-126 的部分。研究结果总结如下：(1)将现有的主NaI(Tl)探测器更换为直径15 cm、长30 cm的更大的NaI(Tl)探测器，伽马射线灵敏度提高(2)对Zr-90、91、92、94和Sn-116、117、118、119、120、122、124进行了系统测量。完成了Zr-90,91,92,94和Sn-117,118,119的数据处理，并推导了这些同位素的俘获截面和俘获伽马能谱。(3)推导的俘获截面和俘获伽马能谱。利用核反应理论中的统计模型对Zr-90,91,92,94和Sn-117,118,119的光谱进行了理论分析，获得了Zr-90,91,92,94和Sn-117,118,119的光谱信息。 (4)根据获得的信息对长寿命裂变产物Zr-93和Sn-126的快中子俘获截面进行了评价，并得出评价值暂定获得。