Variation of environmental neutron flux with altitude and depth of both water and soil

作     者：K.KOMURA N.K.AHMED A.H.EL-KAMEL A.M.M.YOUSEF 

作者机构：Low Level Radioactivity LaboratoryKanazawa UniversityWake TatsunokuchiIshikawa 923-1224JapanPlrysics DepartmentFaculty of Science.South Valley UniversityKenaEgyptPhysics DepartmentFaculty of ScienceAssiut UniversityAssiutEgyptPhysics DepartmentFaculty of Science.South Valley UniversityKenaEgypt 

出 版 物：《Nuclear Science and Techniques》 (核技术（英文）)

年 卷 期：2004年第15卷第4期

页      面：248-256页

核心收录：

学科分类：08[工学] 0827[工学-核科学与技术] 082701[工学-核能科学与工程] 

主　　题：环境中子流 金活化作用 γ射线光谱学 环境放射学 水 土壤 

摘      要：Applying the extreme low-level γ-ray spectroscopic analysis the environmental neutron flux is measured using different moderator construction and environment through the reaction 197Au (n, γ) 198Au. The contribution of thermal and resonance neutrons is separated using the cadmium difference technique, while fast neutrons are measured by the paraffin moderator. The results of altitude dependence of the neutron flux are discussed. The thermal neutron flux near the surface of sea water is less than its value at 100 cm over ground near sea water, while the value over the surfaces of fresh water is higher than that near the surface of sea water. Also the thermal neutron flux at 5 cm soil depth increases, then decreases to its original value at 10 cm depth and still constant until 25 cm, then decreases rapidly to reach 27% of its original value at 60 cm depth. The soil compositions, corresponding neutron temperatures and effective absorption cross sections of earth are the most effective factors on the equilibrium region of thermal neutrons in the ground.