广东珠海地表介质中^(238)U、^(232)Th和^(40)K的活度水平

^(238)U、^(232)Th and ^(40)K Radioactivity Level of Soil and Concrete Floor in Zhuhai, Guangdong Province, China

采用就地伽马能谱测量方法对珠海市进行了以评价环境电离辐射水平为目的测量,实测面积100km2,970个测点。采用NaI(Tl)闪烁伽马谱仪实测珠海风化花岗岩中40K、238U和232Th的比活度分别为654·2±338·0,85.7±31.6和159.8±49.0Bq·kg-1;第四纪沉积物中则分别为:632·3±75·1,35.2±14.6和70.2±18.6Bq·kg-1。研究结果表明,地表介质中40K、238U和232Th主要来源于晚侏罗纪黑云母二长花岗岩,其比活度与地质背景密切相关。

In-situ gamma-ray spectrometer survey is carried out in Zhuhai, Guangdong province from 2002 to 2003 in order to estimate the radiation level of natural radionuclides. Measured area is more than 100 km2 and 970 sites with NaI(Tl) (φ 75 mm×75 mm) gamma-ray spectrometer. The specific activity of 40K、 238U and 232Th are 654.2±338.0, 85.7± 31.6, and 159.8±49.0 Bq·kg -1 in weathered granite, and 632.3±75.1, 35.2±14.6 and 70.2±18.6 Bq·kg -1 in the sediments, respectively. Biotite Granite is the source of 40K、 238U and 232Th in the medium on ground in Zhuhai. The specific activity of natural radionulides have significant dependence relation with geological background, such as lithology.