空气中天然放射性粒子的沉积率

Deposition rate of natural radioactive particles from atmosphere\

目的 采用累积法直接测量天然放射性粒子在墙壁、地面上的平均沉积率。解决用累积法测量2 2 2 Rn短寿命子体非结合态份额 (fA 值 )的难题 ,以提高肺剂量评价精度。方法 沉积率、氡浓度和fA 值分别采用CN径迹法、静电累积法和筛网法测量。结果 福州市室内外沉积率的年平均值为 3 9～ 2 6 5 [粒子数·10 -4 / (cm2 ·s) ],氡浓度与沉积率呈现相同的变化规律 ,非结合态RaA粒子的铅直下降速度为 0 4～ 1 1cm/s。结论 CN径迹法可有效地测量氡子体对地面等的沉积率 ,本研究所采用的累积法也是测量平均fA 值和粒子沉积速度的有效手段 ,从而有可能使肺剂量的评价精度得到提高。

Objective\ To measure the deposition rate of natural radioactive particles from atmosphere by passive method,so as to offer a feasible method for the measurement of f A value(free RaA fraction),thus resulting in the advancement of the precision in the evaluation of the lung dose. Methods The deposition rate,radon concentrations and f A value were measured by CN bare method,electrostatic integrating radon monitor and mesh,respectively. Results The annual mean deposition rates were 3.9 to 26.5(10 -4 /cm 2·s)and the deposition velocities were found to be 0.4 to 1.1(cm/s)for outdoors and indoors in Fuzhou city. Conclusion The CN bare method is good for the measurement of the deposition rate of natural radioactive particles from atmosphere,thereby possibly advancing the precision of the evaluation of the lung dose.The results of this study agree fairly well with the values reported by other researchers.\;