Abstract

We investigate the contribution of gamma radiation of natural radionuclides constituting the Earth crust, radioactive emanations, and their decay product in the ground to the rate of production of ion pairs in the atmosphere against the background of ionization of the atmosphere by radioactive gases exhaled to the atmosphere from the ground and propagating together with their short-lived daughter products. The radon flux density to the atmosphere is estimated by three methods: the reservoir method, the integration of altitude profiles of volume activity of radon, based on gamma spectroscopic observations and the diffusion model. The distribution of the gamma radiation dose from the earth radionuclides in the soil and the atmosphere is calculated using Gleant4 software. The propagation of the radon isotopes and their decay products in the atmosphere is calculated simulated using large eddy simulation supplemented with kinematic simulation of subgrid flux of a passive scalar. It is shown that depending on the specific activity of radionuclides in the ground, the soil parameters, and the turbulent regime of the atmosphere, the total contribution of gamma radiation to the ion pair production rate in the atmospheric boundary layer is approximately from 1 to 20% and increases upon a decrease in the penetrability of the upper ground layer for radioactive emanations.

中文翻译：

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地壳放射性核素和放射性放射物对大气电离的光子成分的贡献

摘要

我们以呼出到大气中的放射性气体电离大气为背景，研究构成地壳的天然放射性核素的伽马辐射、放射性发射及其在地下的衰变产物对大气中离子对产生速率的贡献。来自地面的大气并与其短命的子产品一起传播。大气氡通量密度通过三种方法估算：水库法、基于伽马能谱观测和扩散模型的氡体积活度高度剖面积分。使用Gleant4软件计算地球放射性核素在土壤和大气中的伽马辐射剂量分布。氡同位素及其衰变产物在大气中的传播是使用大涡模拟并辅以被动标量子网格通量的运动学模拟来模拟计算的。结果表明，根据地下放射性核素的比活度、土壤参数和大气的湍流状况，伽马辐射对大气边界层中离子对产生速率的总贡献约为 1 至 20 ％并且随着上地层对放射性发射的渗透性的降低而增加。