Activated Charcoal Cumulated Adsorption Method for Measuring Radon Exhalation Rate from Soil
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摘要: 为解决大面积多点快速土壤氡析出率测量问题, 设计开发并进行了土壤氡析出率活性炭累积吸附法的方法技术研究.在参考氡析出率装置和野外实验数据的基础上, 进行了测量装置及材料的选择、装置刻度、野外累积暴露时间、活性炭盒吸附氡有效衰变常数等研究.通过2002-2003年22次重复观测, 北京西北郊区粘土类土壤氡析出率平均值为20.15mBq.m-2.s-1, 最大值和最小值分别为26.75和13.49mBq.m-2.s-1, 标准偏差为3.55mBq.m-2.s-1.与仪器静电收集法比对结果表明, 两种方法的相对误差小于±10%.实验结果表明: 活性炭方法测量结果稳定可靠, 简便易行, 适用于全国大面积土壤氡析出率调查.Abstract: We designed and developed an activated charcoal cumulated adsorption method for measuring radon exhalation rate from soil to perform rapid observation at many sites in a large area. Based on the data of measurements on the radon exhalation facility and real-time soil radon exhalation rate in the field, we studied the types of the activated charcoal and sampling device, accumulated exposure time and radon effective decay constant. We investigated the soil radon exhalation in a university yard (sandy loam) from 2002-2003. The average of radon exhalation rate is 20.15 mBq·m-2·s-1; the standard deviation is 3.55 mBq·m-2·s-1, and the variety ranges from 13.49 to 26.75 mBq·m-2·s-1. By comparison, the results of activated charcoal absorption and an equipment of electrostatic collection are coincident with each other. The results revealed that the method of activated charcoal absorption is practical, feasible and rapid for measuring the 222Rn exhalation rate from soil in the field.
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图 1 活性炭累积吸附装置示意图(Wang and Xiao, 2004)
Fig. 1. The sketch map of device of activated charcoal cumulated adsorption (Wang and Xiao, 2004)
表 1 不同累积时间求得的转换系数
Table 1. Factor k at corresponding accumulated exposure time
表 2 活性炭累积法与静电收集法土壤氡析出率测量结果对比
Table 2. The comparison of the results between activated charcoal adsorption and electrostatic collection
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[1] Al-Jarallah, M. I., 2001. Radon exhalation fromgranites usedin Saudi Arabia. Journal of Environmental Radioactivity, 53 (1): 91-98. doi: 10.1016/S0265-931X(00)00110-7 [2] Al-Jarallah, M. I., Abu-Jarad, F., Fazal-ur-Rehman, 2001. Determination of radon exhalation rates fromtiles usingactive and passive techniques. Radiation Measurement, 34 (1-6): 491-495. doi: 10.1016/S1350-4487(01)00213-X [3] Chen, L., Xie, J. L., Huang, L., 1998. Measurement and related factors about radon surface exhalation rate. Radiation Protection Bulletin, 18 (6): 28-36 (in Chinese with English abstract). [4] Fazal-ur-Rehman, Al-Jarallah, M. I., Musazay, M. S., et al., 2003. Application of the can technique and radon gasanalyzer for radon exhalation measurements. Applied Radiation and Isotopes, 59 (5-6): 353-358. doi: 10.1016/S0969-8043(03)00196-9 [5] Fu, J., Han, Y. Z., Zhang, B., 2003. Measuring radon exhalation rate fromuraniumtailings by theinstrumentality ofactive carbon absorption. Radiation Protection Bulletin, 23 (2): 32-35 (in Chinese with English abstract). [6] Guo, Q. J., Cheng, J. P., 2004. Measurement of 222Rn/220Rn progeny and exhalation rates for 222Rn/220Rn from soilin Zhuhai area. Radiation Protection, 24 (2): 110-115 (in Chinese with English abstract). [7] Gou, Q. L., Zhang, Z. H., 1998. Discussion on the formula ofelectrostatic collection radon exhalation rate monitor. Atomic Energy Science and Technology, 32 (5): 420-426 (in Chinese with English abstract). [8] Ren, T. S., 2001. Source, level and control of indoor radon. Radiation Protection, 21 (5): 291-299 (in Chinese with English abstract). [9] Singh, A. K., Sengupta, D., Prasad, R., 1999. Radon exhalationrate and uranium esti mation in rock samples from Biharuranium and copper mines using the SSNTD technique. Applied Radiation and Isotopes, 51 (1): 107-113. doi: 10.1016/S0969-8043(98)00152-3 [10] Sun, K. N., Guo, Q. J., Cheng, J. P., 2005. The effect ofsome soil physical parameters on soil radon concentration and radon exhalationfromsoil surface. Chin. J. Radio. Med. Prot. , 25 (1): 78-80 (in Chinese with Eng-lish abstract). [11] UNSCEAR, 1993. United Nations scientific committee on theeffects of atomic radiation, sources and effects of ionizingradiation, United Nations1993. UNSCEAR, New York. [12] Wang, N. P., Xiao, L., 2004. Adetailed study of indoor 222Rn level associate with 222Rn exhalation fromsedi ment andthe character of sedi ment in high-background weatheredgranite area, south China. http://www.irpa11.com/mew/pdfs/6a69pdf. [13] Xiao, L., 2004. Study on a method of soil radon exhalationrate and the correlativity between soil and radon exhala-tion rate and region indoor radon concentrations [Dissertation]. China University of Geosciences, Beijing, 6-33 (in Chinese with English abstract). [14] Yang, Y. X., Wu, X. M., Wu, Y. M., et al., 2002. Experi-mental research on radon exhalation with double-filtermethod. Bulletin of Science and Technology, 18 (1): 38-42 (in Chinese with English abstract). [15] 陈凌, 谢建伦, 黄隆, 1998. 氡面析出率的测量及相关因素的考虑. 辐射防护通讯, 18 (6): 28-36. https://www.cnki.com.cn/Article/CJFDTOTAL-DEFE806.003.htm [16] 付锦, 韩耀照, 张彪, 2003. 活性炭吸附法测量铀矿尾矿氡析出率. 辐射防护通讯, 23 (2): 32-35. doi: 10.3969/j.issn.1004-6356.2003.02.007 [17] 苟全录, 张智慧, 1998. 静电收集式氡析出率仪的计算公式讨论. 原子能科学技术, 32 (5): 420-426. https://www.cnki.com.cn/Article/CJFDTOTAL-YZJS805.006.htm [18] 郭秋菊, 程建平, 2004. 珠海市环境空气中222Rn、220Rn子体水平及土壤析出率测量. 辐射防护, 24 (2): 110-115. doi: 10.3321/j.issn:1000-8187.2004.02.005 [19] 任天山, 2001. 室内氡的来源, 水平和控制. 辐射防护, 21 (5): 291-299. doi: 10.3321/j.issn:1000-8187.2001.05.005 [20] 孙凯男, 郭秋菊, 程建平, 2005. 土壤物理性质对土壤氡浓度及地表氡析出率的影响. 中华放射医学与防护杂志, 25 (1): 78-80. doi: 10.3760/cma.j.issn.0254-5098.2005.01.032 [21] 肖磊, 2004. 土壤氡析出率测量方法及其与区域环境氡浓度相关性研究(硕士学位论文). 北京: 中国地质大学, 26-33. [22] 杨亚新, 吴信民, 吴雅梅, 等, 2002. 用双滤膜法测定氡析出率的实验研究. 科技通报, 18 (1): 38-42. doi: 10.3969/j.issn.1001-7119.2002.01.008