权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Experimental inspection of the (n, gamman') reaction in heavy nuclei

重核中 (n, gamman) 反应的实验检查

基本信息

批准号：
07680522
负责人：
BABA Mamoru
金额：
$ 1.41万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07680522/
关键词：
(n, gamman, ) reaction Bi TOF method correlation exp Li(p, n) source NE213 dynamic-biasing 中性子反応 (n,γn′)反応低バックグラウンド信号対雑音比飛行時間法 n・γ相関測定断面積スペクトル

项目摘要

The present research aims at the experimental inspection of (n, gamman, ) reaction using a Bi sample and TOF and/or correlation methods.1.Detector preparation :We supplemented electronics circuits necessary to do experiments, and prepared a BaF_2 gamma-ray detector having a good energy resolution (<9% for Cs-137 gamma-ray) and a timing resolution (<600ps). For TOF experiments, we optimized the performance of an existing NE213 (5"-diam x2"thick) detector for pulse-height, TOF,and pulse-shape properties, and developed a data processing method based on a dynamic-biasing technique using three-parameter data. It enabled measurements of neutrons lower than 20 ke V.2.Measurement and AnalysisWe carried out TOF experiment for 1-2 MeV neutrons first because problem were foreseen in the correlation methods because of the uncertainty in the overall gamma-ray detection efficiency and the gamma-ray contamination ratio into the neutron detector. The TOF experiments employed a quasi-monoenergetic ^7Li (p, n) source because the updated detector system proved that the monoenergetic T(p, n) source with a Ti-T target have backgrounds neutrons. Up to now, we could not confirm any significant difference between the spectra for Bi and C,Al which have no appreciable (n, gamman, ) cross sections. Thus we have not confirmed yet the evidence of the (n, gamman, ) process. Nevertheless, further experiments will be worthwhile using an updated experimental system and method established in this study because the signal-to-noise ratio is good enough to observe reactions with cross section<1mb/(Sr MeV). The experimental system developed in the present study is useful for other research works too.

1.探测器的制备：补充了实验所需的电子学电路，制备了具有良好能量分辨率（对Cs-137 γ射线<9%）和时间分辨率（<600 ps）的BaF_2 γ射线探测器。对于飞行时间实验，我们优化了现有的NE 213（5”直径x2“厚）探测器的脉冲高度，飞行时间和脉冲形状属性的性能，并开发了一种基于动态偏置技术的数据处理方法，使用三参数数据。2.测量与分析我们首先进行了1-2 MeV中子的TOF实验，因为在相关方法中预见到了问题，因为在总的γ射线探测效率和γ射线进入中子探测器的污染率的不确定性。飞行时间实验使用了准单能^7Li（p，n）源，因为更新的探测器系统证明了带有Ti-T靶的单能T（p，n）源具有本底中子。到目前为止，我们不能确认Bi和C，Al的光谱之间有任何显着差异，它们没有明显的（n，γ，）截面。因此，我们还没有证实（n，gamman，）过程的证据。尽管如此，使用本研究中建立的更新的实验系统和方法进行进一步的实验是值得的，因为信噪比足够好，可以观察到截面<1 mb/（Sr MeV）的反应。本研究所开发的实验系统对其他研究工作也有一定的参考价值。