【摘要】 设计加工了一种普通的活性炭盒,采用加滤膜和不加滤膜两种方法被动取样,用实测的相对效率为67%的HPGe探测器测量同一时间、同一地点的相对氡浓度,结果两种方法给出的值差异不大。实验证明在目前采用的条件下,无法测出220Rn的浓度。从实验可知,用HPGeγ谱法可明显区分212Pb238.63keV峰和214Pb242.00keV峰,样品中295.22、351.93、609.31keV峰计数都明显高于空白样品计数。如果进一步进行刻度,可准确测量222Rn的浓度。提出了高效率γ谱仪法测量氡浓度中的真符合相加问题,并对特征峰选择进行了讨论。本方法不必刻度效率而得到测量点的相对浓度,可以用于比较季节、温度、通风等条件变化引起的氡浓度变化规律的研究和评估除氡措施的效果等。更多还原

【Abstract】 A common activated charcoal radon collector has been designed. Passive activated charcoal indoor radon samples with and without filters of several representative sites have been analyzed by a HPGe detector of 67% relative efficiency, and the relative radon concentration has been compared. The differences are not significant. It has been proved that ²²⁰Rn concentration cannot be measured by using our procedures. The full energy peaks of ²¹²Pb 238.63keV and ²¹⁴Pb 242.00keV can be separated apparently, 295.22keV,351.93keV, 609.31keV peaks are higher then blank sample . ²²²Rn concentration can be measured if the whole system is carefully calibrated. The true coincidence summing correction in analyzing radon by high-resolution γ spectrometry has been put forward, and the selection of full energy γ-ray peaks has been discussed. The relative radon concentration of the same site can be compared by using this method, which need not to be calibrated. It can also be used in the study of radon concentration variation vs. seasons, temperature and ventilation , etc. It can also be used to evaluate the effects of radon preventing methods.更多还原