Ademola J A, Oguneletu P O
Department of Physics, University of Ibadan, Nigeria.
J Environ Radioact. 2005;81(1):107-13. doi: 10.1016/j.jenvrad.2004.12.002.
Thirty-two samples of concrete building blocks were collected from different block making industries in Ibadan. The radioactivity concentrations of the natural radionuclides in the samples were determined by gamma-ray spectrometry with a NaI(Tl) detector. The radioactivity concentrations varied from 6.2 to 57.5 Bq kg(-1), 12.4 to 64.9 Bq kg(-1) and 95.3 to 766.1 Bq kg(-1) for 226Ra, 232Th and 40K, respectively. The radium equivalent activities of the 32 samples varied from 51.3 to 175.7 Bq kg(-1). Radiation exposure levels in 30 dwellings were determined using LiF thermoluminescent dosimeters. The annual equivalent dose rates varied from 0.318 to 0.657 mSv y(-1) with a mean of 0.433 mSv y(-1). The annual effective dose rate to the whole body was calculated as 0.236 mSv y(-1), which is less than that (mean) estimated by UNSCEAR for normal background areas.
从伊巴丹不同的砌块制造行业收集了32个混凝土砌块样本。使用碘化钠（铊）探测器通过伽马射线能谱法测定了样本中天然放射性核素的放射性浓度。对于镭-226、钍-232和钾-40，放射性浓度分别在6.2至57.5贝克勒尔每千克、12.4至64.9贝克勒尔每千克和95.3至766.1贝克勒尔每千克之间变化。32个样本的镭当量活度在51.3至175.7贝克勒尔每千克之间变化。使用氟化锂热释光剂量计测定了30处住宅的辐射暴露水平。年当量剂量率在0.318至0.657毫希沃特每年之间变化，平均值为0.433毫希沃特每年。全身的年有效剂量率计算为0.236毫希沃特每年，低于联合国原子辐射效应科学委员会对正常本底地区估计的（平均值）。
