ABSTRACT

Radon is a naturally occurring radioactive gas; generated during the decay process of radium, when alpha particles start to be emitted, turning the radium into radon. The rate of radon gas that escapes from the soil into the atmosphere is called radon exhalation rate. In this study, radon, radium, and both radon surface and mass exhalation rates were measured for 40 samples of soil at four sampling depths (10, 20, 30, and 40 cm) in three districts of Duhok province. For the radon measurement, alpha-sensitive RAD7 detector was used. While radium concentration measured by well type NaI (Tl) detector. Analysis, shows radon surface exhalation rate vary from 24 ± 10.7 to 57 ± 2.5 Bq.m⁻²h⁻¹ with an average value of 38.7 ± 8.9 Bq.m⁻²h^−1. While mass exhalation rate vary from 1.2 ± 0.9 to 6.7 ± 1.6 Bq.kg⁻¹.h⁻¹ with an average of 4.2 Bq.kg⁻¹.h⁻¹. Furthermore, the results showed that radon exhalation rate and radon concentrations in soil have direct proportion to soil depths. Overall, radon concentration, radium content and both surface and mass exhalation rate in all sample points present a good correlation and less than global mean average recommendation [30].

摘要

氡是一种天然存在的放射性气体；在镭衰变过程中产生，当α粒子开始发射时，镭变成氡。氡气从土壤中逸出到大气中的速率称为氡气呼出率。在这项研究中，在杜霍克省的三个地区测量了四个采样深度（10、20、30 和 40 厘米）的 40 个土壤样本的氡、镭以及氡表面和质量呼出率。对于氡测量，使用了α敏感的RAD7探测器。而镭浓度则由井式 NaI (Tl) 检测器测得。分析表明氡表面呼出速率从 24 ± 10.7 到 57 ± 2.5 Bq.m ^-2 h ^{-1 变化}，平均值为 38.7 ± 8.9 Bq.m ^-2 h ^-1。而大量呼气速率从 1.2 ± 0.9 到 6.7 ± 1.6 Bq.kg ^-1 .h ^-1不等，平均为 4.2 Bq.kg ^-1 .h ^-1。此外，结果表明氡的呼出速率和氡在土壤中的浓度与土壤深度成正比。总体而言，所有采样点的氡浓度、镭含量以及表面和质量呼出率都呈现出良好的相关性，并且低于全球平均推荐值 [30]。