Monte-Carlo simulation of cement neutron field distribution characteristics in PGNAA  

作　　者：YANG Jianbo YANG Yigang LI Yuanjing TUO Xianguo LI Zhe LIU Mingzhe CHENG Yi MU Keliang WANG Lei 

机构地区：[1]Department of Engineering Physics,Tsinghua University [2]Chengdu University of Technology [3]State Key Laboratory of Geohazard prevention & Geoenvironment Protection [4]Nuclear Power Institute of China

出　　处：《Nuclear Science and Techniques》2012年第6期337-343,共7页核技术（英文）

基　　金：Supported by National Natural Science Foundation for Distinguished Young Scholar(41025015);NSFC(40974065,11105132);Province Key Technology R&D Program(2011FZ0055);National High Technology Research and Development Program of China(2012AA063501);the Basic Research for Application of Sichuan Province(2012JY0109);China Postdoctoral Science Foundation(2012M520245)

摘　　要：The distribution characteristics of the neutron field in cement was simulated using the MCNP code to comply with the requirements of an online Prompt Gamma Neutron Activation Analysis system.Simulation results showed that the neutron relative flux proportion reduced with increasing cement thickness.When the cement thickness remains unchanged,the reduced proportion of thermal neutrons increases to a small extent,but the epithermal, intermediate,and fast neutrons will decrease according to the geometric progression.H element in the cement mainly affects the reduction of fast neutrons and other single-substance elements,e.g.,O,Ca,56Fe,Si,and Al.It also slows down the reduction of the fast neutrons via inelastic scattering.O contributes more than other elements in the reduction of fast neutrons.Changing the H content affects the thermal,epithermal,intermediate,and fast neutrons, while changing the Ca,Fe,and Si contents only influences the thermal,epithermal,and intermediate neutrons;hence, there is little effect on the reduction of fast neutrons.The distribution characteristics of the neutron field in cement was simulated using the MCNP code to comply with the requirements of an online Prompt Gamma Neutron Activation Analysis system.Simulation results showed that the neutron relative flux proportion reduced with increasing cement thickness.When the cement thickness remains unchanged,the reduced proportion of thermal neutrons increases to a small extent,but the epithermal, intermediate,and fast neutrons will decrease according to the geometric progression.H element in the cement mainly affects the reduction of fast neutrons and other single-substance elements,e.g.,O,Ca,^（56）Fe,Si,and Al.It also slows down the reduction of the fast neutrons via inelastic scattering.O contributes more than other elements in the reduction of fast neutrons.Changing the H content affects the thermal,epithermal,intermediate,and fast neutrons, while changing the Ca,Fe,and Si contents only influences the thermal,epithermal,and intermediate neutrons;hence, there is little effect on the reduction of fast neutrons.

关 键 词：蒙特卡罗模拟 中子活化 PGNAA 水泥 特征 场分布 在线分析系统 MCNP程序 

分 类 号：O571.5[理学—粒子物理与原子核物理]