活性炭测氡γ总计数的理论计算及实验验证

摘要

In this paper,a method for total-count T-ray measurement of radon in activated carbon is presented,with correction for decay and time delay for the measurement based on the decay of radon and its progeny.Simulation of the total-cotmts of γ-rays from radon-absorbed activated carbon was performed.The results show that the time-dependent calculated curve of γ-ray total-counts agrees well with the measured one.The front part of the curve,where the counts increase first and decrease later,is the time delay for the measurement.The duration of delayed measurement is closely related to the duration of radon absorbed by activated carbon,but it has nothing to do with the radon concentration.And the longer the adsorption duration,the shorter is the time delay.Then,the counts follow the function of e-0.000125t,which is also independent of the concentration of radon absorbed by activated carbon.%根据氡及其子体的相继衰变规律,对均匀吸附环境氡的活性炭的γ总计数进行了理论推导,得到了活性炭γ总计数的计算公式;并对活性炭γ总计数进行了模拟计算.结果表明:活性炭取出后γ总计数随时间的变化曲线与实测曲线相吻合;在曲线的前段,计数先增大后减小,为活性炭的静置区,静置时长(即静置区的宽度)与活性炭吸附氡的时长密切相关,与氡浓度大小无关,吸附时间越长,所需静置时间越短;在曲线的后段,计数以e-0.000125t函数逐渐衰减,这一规律与氡浓度的大小无关.