8.0MeV中子与天然镓作用的弹性散射微分截面实验研究  

Experimental study of elastic scatting differential cross section of secondary neutron for natural gallium at 8.0MeV incident neutrons

作　　者：王学浩 黄翰雄 兰小飞 阮锡超 张奇玮 任杰 孙琪 栾广源 刘超 丁琰琰 王金成 麻旭 胡志杰 郭明伟 江历阳 WANG Xuehao;HUANG Hanxiong;LAN Xiaofei;RUAN Xichao;ZHANG Qiwei;REN Jie;SUN Qi;LUAN Guangyuan;LIU Chao;DING Yanyan;WANG Jincheng;MA Xu;HU Zhijie;GUO Mingwei;JIANG Liyang(School of Physics and Astronomy,China West Normal University,Nanchong 637002,China;Institute of Nuclear Physics,Chinese Academy of Atomic Energy,Beijing 102413,China)

机构地区：[1]西华师范大学物理与天文学院,南充637002 [2]中国原子能科学院研究院核物理研究所,北京102413

出　　处：《核技术》2021年第12期63-68,共6页Nuclear Techniques

基　　金：国家自然科学基金面上项目(No.11975318)资助。

摘　　要：基于镓中子反应截面实验数据的匮乏和评价数据的分歧,利用中国原子能科学研究院串列加速器上的多探测器快中子飞行时间谱仪,开展了8.0 MeV中子与天然镓样品的弹性散射微分截面实验研究。实验测量了21个角度的弹性散射微分截面数据,使用n-p散射作为标准截面进行归一。采用Monte-Carlo方法,对中子在样品中的中子注量率衰减、多次散射及实验的有限几何进行了修正,通过模拟得到次级中子飞行时间谱(Time-offlight,TOF)与实验测量的TOF谱进行直接比较的方法获得中子与镓作用的弹性散射微分截面。实验测量结果与评价数据的对比分析结果表明:当前几大数据库中,CENDL-3.2数据库的结果更贴近实验测量结果。本实验为8.0 MeV中子能区的首次实验测量,澄清了几个评价库数据之间的分歧,为核数据评价、理论模型改进提供了实验数据支撑。[Background]Due to the special physical properties of gallium,gallium is considered to be used as reactor coolant in the future.Therefore,a full set of gallium neutron data is needed.However,the experimental data of gallium in EXFOR(Nuclear reaction experimental data)database is rare.There are also some discrepancies among the evaluation data.[Purpose]This study aims to obtain elastic scatting differential cross section for natural gallium at 8.0 MeV incident neutrons,so as to fill the blanks of the neutron data of gallium in the database and clarify the discrepancy among the evaluation data.[Methods]First of all,the elastic scatting differential cross section data of natural gallium was measured at 21 different laboratory angles from 20°to 140°by using the multi-detector fast neutron time-of-flight(NTOF)spectrometer on HI-13 tandem acceleration at the China Institution of Atomic Energy(CIAE).The cross sections of gallium were normalized by n-p elastic scatting cross section,and the quality of data was improved by many methods applied to the measurement and data analysis.Then,the Monte-Carlo code STREUER was employed to rectify the neutron flux attenuation,multiple scattering and the finite geometry of the experiment.Finally,the measured TOF spectra were compared with that of simulated to determine experimental scatting differential cross section of 8.0 MeV incident neutrons.[Results&Conclusions]The results of cross section of secondary neutron for natural gallium are the world’s first experimental data in the 8.0 MeV energy region.Compared with the evaluated data,the measured data is generally in good agreement with CENDL-3.2 data,but inconsistent with ENDF/B-8.0 data and JENDL-4.0 data.The divarication among these three data bases has been clarified by the experimental result,hence of great significance to data evaluation and theoretical model improvement.

关 键 词：次级中子 微分截面 MONTE-CARLO方法 评价数据 

分 类 号：O571.1[理学—粒子物理与原子核物理]