基于中国散裂中子源反角白光中子束线的天然锂中子全截面测量  

Measurement of total neutron cross section of natural lithium at China Spallation Neutron Source Back-n facility

作　　者：张江林 姜炳 陈永浩 郭子安 王小鹤[1,2] 蒋伟 易晗 韩建龙[1,2,3] 胡继峰 唐靖宇[4,5] 陈金根 蔡翔舟[1,2,3] Zhang Jiang-Lin;Jiang Bing;Chen Yong-Hao;Guo Zi-An;Wang Xiao-He;Jiang Wei;Yi Han;Han Jian-Long;Hu Ji-Feng;Tang Jing-Yu;Chen Jin-Gen;Cai Xiang-Zhou(Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China;Innovative Academy in TMSR Energy System,Chinese Academy of Sciences,Shanghai 201800,China;University of Chinese Academy of Sciences,Beijing 100049,China;Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China;Spallation Neutron Source Science Center,Dongguan 523803,China)

机构地区：[1]中国科学院上海应用物理研究所,上海201800 [2]中国科学院先进核能创新研究院,上海201800 [3]中国科学院大学,北京100049 [4]中国科学院高能物理研究所,北京100049 [5]散裂中子源科学中心,东莞523803

出　　处：《物理学报》2022年第5期123-130,共8页Acta Physica Sinica

基　　金：中国科学院战略性先导科技专项(批准号:XDA02010000);中国科学院前沿科学重点研究项目(批准号:QYZDY-SSW-JSC016);国家自然科学基金重大项目(批准号:11790321)资助的课题.

摘　　要：锂是熔盐堆燃料载体盐的主要材料之一,其中子核反应截面数据是熔盐堆芯中子物理设计及堆芯长期安全运行中的重要基础数据.本工作基于中国散裂中子源反角白光中子束线(CSNS Back-n)飞行时间谱仪,利用中子全截面测量谱仪(NTOX),采用透射法测量了天然锂中子全截面.实验中,中子飞行距离约为76.0 m,采用15.0 mm和8.00 mm两种厚度的天然锂金属样品,在0.4 eV-20 MeV中子能量范围内测得了统计计数较好的中子全截面.特别是在keV及以下能区增补了实验数据,为锂的核数据评价工作提供了更加丰富和可靠的实验数据.在此基础上,采用1/v律和R矩阵理论对MeV以下能区的新测量数据进行了理论分析,获得了7Li和6Li在260 keV能量附近的中子共振参数.Lithium is one of the main materials of fuel carrier salt in molten salt reactors.Its neutron cross section provides an important basic datum for physical design of molten salt reactor core and for evaluating the safety of the core during operation.The total neutron cross sections of natural lithium samples with thickness values of 8.00 mm and 15.0 mm are measured,respectively,in an energy range from 0.4 eV to 20 MeV by using a neutron total cross section spectrometer(NTOX)with the transmission method at the Back-n white neutron source of China Spallation Neutron Source(CSNS Back-n)with a 76.0 m time-of-flight path.High quality experimental data are obtained,especially in the energy region of keV and below,which supply a significative supplement of the data,thereby providing more abundant and reliable experimental data for nuclear data evaluation of lithium.Additionally,a theoretical analysis is carried out under the guidance of 1/v law and the multilevel R-matrix theory.And the resonance parameters of n+6,7Li reaction around the energy of 260 keV are extracted from the measured data.

关 键 词：中子全截面 天然锂 中国散裂中子源 Back-n 

分 类 号：O571.55[理学—粒子物理与原子核物理]