Upgrade of a Highly Sensitive Monitor for Atmospheric Radon Measurement
Upgrade of a Highly Sensitive Monitor for Atmospheric Radon Measurement
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DOI：
10.3390/atmos12101257
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发表时间：
2021-09
期刊：
影响因子：
2.9
通讯作者：
Lei Zhang;Yunlong Mao;Hao Wang;Q. Guo
中科院分区：
文献类型：
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作者：
Lei Zhang;Yunlong Mao;Hao Wang;Q. Guo
大气氡是一种理想的示踪剂，在大气科学中有着广泛的应用。为了满足连续在线测量大气氡浓度的需要，在饭田测量系统的基础上，研制了一种改进的静电收集法测氡仪。实现了两项重大改进。首先，使用18 mm × 18 mm的Si-PIN探测器和多通道分析系统来区分不同的α粒子。第二，用新的膜干燥系统代替P2 O 5干燥剂，并通过湿度校正系数来校正湿度的影响。进行了详细的标定和比对实验，并进行了一年的连续测量。结果表明，测量灵敏度为24.3 cph/（Bq·m−3），在绝对湿度为0.34 g·m− 3的条件下，1 h循环的检测下限为0.2 Bq·m−3。北京的年平均氡浓度为11.1 ± 4.0 Bq·m−3，在2018年10月15日至2019年10月1日期间从2.8 Bq·m − 3变化到30.3 Bq·m−3。改进后的监测仪数据采集速度快，性能良好，适合于大气氡的长期观测。
Atmospheric radon is an ideal tracer that is widely used in atmospheric science. To meet the need fora continuous online measurement of atmospheric radon concentration, an upgraded radon monitor based on an electrostatic collection method was developed following Iida’s measurement system. Two major improvements have been realized. First, an 18 mm × 18 mm Si-PIN detector and a multi-channel analysis system were used to distinguish different alpha particles. Second, the P2O5 desiccant was replaced by a new membrane drying system, and the influence of humidity was corrected by a humidity correction coefficient. Calibration and comparison experiments were carried out in detail, and a one-year continuous measurement was also performed. Results showed that the measurement sensitivity was evaluated to be 24.3 cph/(Bq·m−3), and the lower level detection limit was 0.2 Bq·m−3 for a 1-h cycle at the absolute humidity of 0.34 g·m−3. The annual average radon concentration of Beijing was 11.1 ± 4.0 Bq·m−3, which changed from 2.8 Bq·m−3 to 30.3 Bq·m−3 between 15 October 2018 and 1 October 2019. The upgraded monitor’s high data acquisition rate and good performance indicate that it is suitable for long-term observation on atmospheric radon.