中文摘要：

应用ELPI系统、α谱仪和能量甄别法测量程序,建立了1套220 Rn子体气溶胶活度粒径分布的测量方法;利用该方法收集了南华大学220 Rn实验室不同粒径的220 Rn子体气溶胶,并进行了220 Rn子体气溶胶活度粒径分布测量。实验结果表明：ThB气溶胶的活度中位粒径（AMAD）平均值为237nm,ThC气溶胶的AMAD平均值为245nm。该方法简便易行、测量周期短,能实时得到220 Rn子体气溶胶粒子数粒径分布的情况,能同时得到ThB和ThC气溶胶的活度粒径分布情况,且能谱法的测量精度也相对较高。

英文摘要：

The method for measuring 220Rn progeny aerosol activity particle size distributions was introduced through ELPI system,α spectroscopy and the energy discrimination method.The different particle sizes of the 220Rn progeny aerosols were collected and the activity size distributions in the 220Rn laboratory of the University of South China were measured by this method.The experiment results show that the activity median aerodynamic diameter（AMAD） of ThB aerosol is 237 nm,and that of ThC is 245 nm.The simple and quick method can be used to monitor the particle size distributions of 220Rn progeny aerosol in real time,the aerosol activity size distributions of ThB and ThC can be obtained by this method at the same time,and the measurement accuracy of the energy spectrum is higher than that of custom method.