氡子体比的现场测量及其对剂量转换系数的影响

摘要

The activity ratio of radon progeny is the ratio of radon short‐lifetime progeny (218 Po , 214 Pb and 214 Bi) activity concentration .The activity ratio of radon progeny is one of the most significant parameters in the calculation of radon progeny dose conversion factor ,which can be affected by many environmental factors ,such as the characteristics of aerosols ,ventilation rate and so on .In order to add and update the data of activity ratios of radon progeny in the typical urban environments ,and analysis its influence on the dose conversion factor ,the field measurement studies were performed in the typical urban indoor and outdoor environments by a portable α spectrometer ,and the corre‐sponding radon progeny dose conversion factor was calculated through LUDEP . The results show that the average disequilibrium activity ratio of radon progeny in the typical urban indoor environment is 1 ∶ 0.59 ∶ 0.58 ,while that in outdoors is 1 ∶ 0.50 ∶ 0.67 . According to the calculation results through LUDEP , the dose conversion factor in indoor environment is 34.28‐34.76 nSv/(Bq ・ h ・ m - 3 ) ,and that in outdoor environ‐ment is 78.11‐79.38 nSv/(Bq ・ h ・ m - 3 ) .%氡子体比是指其短寿命子体218 Po 、214 Pb 、214 Bi 的活度浓度的比值，是氡子体剂量评价中的重要参数，但环境中氡子体比的数据非常有限。为了解和把握城市典型环境中氡子体比的现状，并分析其对剂量转换系数的影响，本文利用便携式α谱仪，现场测量了城市典型室内外环境的氡子体比，并通过分析室内外环境氡子体比数据的特点，讨论了环境氡子体比对剂量转换系数的影响。测量结果显示，城市典型室内环境中氡子体比的平均值为1∶0.59∶0.58，典型室外环境中氡子体比的平均值为1∶0.50∶0.67。因各子体的剂量系数与它们的α潜能呈正比，所以氡子体比对剂量转换系数的影响很小。