活性炭吸附-液闪法测量建材氡析出率的研究

Research on Measurement of Radon Exhalation Rate in Building Material Using Active Carbon Adsorption-Liquid Scintillation Method

为实现建材样品氡析出率的自动化测量,本文研究了一种活性炭吸附-液闪测量建材氡析出率的方法,并通过比较活性炭吸附-液闪法与活性炭吸附-γ能谱法在氡析出率标准装置、铀矿砂水泥砖及发泡砖表面测量值之间的差异,验证该方法的准确性。测量结果表明:活性炭吸附-液闪法可在一定条件下忽略反扩散的影响;根据制备的C-LS-Rn标准源可得其刻度系数为72.36min^(-1)·Bq^(-1),对氡的计数效率为120%;累积时间为72h的最小可探测氡析出率为8.15×10^(-4) Bq/(m^2·s);该方法与活性炭吸附-γ能谱法测量结果的相对偏差为10%左右,在可接受范围内。

In order to achieve automatic measurement of radon exhalation rate in building materials,an active carbon adsorption-liquid scintillation method was introduced.By comparing the measurement results of this method with the active carbon absorption-γenergy spectrum method on the surfaces of the radon exhalation standard device,uranium ore brick and foaming,the accuracy of this method was verified.The results show that the active carbon adsorption-liquid scintillation method can ignore the effect of back-diffusion under certain conditions.Based on the C-LS-Rn standard source,the calibration coefficient of this method is 72.36min^-1·Bq^-1.The counting efficiency of radon is 120% by this method.The minimum detectable radon exhalation rate is 8.15×10^-4 Bq/（m^2·s）when cumulative time is 72 h.The relative deviation of measurement results between these two methods is about 10%,within the acceptable range.