地-空界面上天然中子辐射场的数理模型

A mathematic-physical equation of the natural neutron radiation field on the air-ground interface

本文论述了地-空界面上天然宇宙中子流的来源;将天然中子按能量分为快中子组(En>0.1MeV)与慢热中子组,建立了地-空界面上天然快中子流与慢热中子流粒子注量率随空间分布的数理方程.理论与实测结果相互验证表明:(1)地-空界面上天然中子流粒子注量率随距近地表高度的增加而呈指数规律减小;(2)地-空界面上天然中子流粒子注量率随海拨高程增加而呈指数规律增加;(3)地-空界面上上升中子流粒子注量率随地表介质含水率的增加而减少.

The origins of natural neutron flux on the air-ground interface are described in this paper. A mathematic-physical equation that describes the natural neutron radiation field is theoretically established, in which the natural neutron flux is considered for the fast neutron group （En 〉 0.1MeV） and slow-thermal neutron group according to neutron energy. From the equation, the intensity of fast neutron flux and slowthermal neutron flux is dependent not only on the composition and density of atmosphere, but also on those of soils or rocks, especially, on the water content in soils or rocks. The intensity of neutron flux varies with atmosphere conditions and is inversely proportional to the water content of soils or rocks, which has been verified by the results of measurements on the surface of the Earth.