Manic Vesna, Manic Goran, Nikezic Dragoslav, Krstic Dragana
Department of Physics, University of Niš, PO Box 224, 18000 Niš, Serbia.
Radiat Prot Dosimetry. 2012 Dec;152(4):361-8. doi: 10.1093/rpd/ncs058. Epub 2012 Apr 19.
The absorbed gamma dose rate in indoor air due to natural radionuclides in concrete as a building material was determined in this work. The dose rate conversion factors for (238)U, (232)Th and (40)K, for standard rooms as well as rooms with different sets of dimensions, were evaluated by the point kernel technique, using Harima (geometric progression) build-up factors. The values of the conversion factors, in units (nGy h(-1) (Bq kg(-1))(-1)) calculated for the standard room are: 0.76, 0.91 and 0.070, respectively for (238)U, (232)Th and (40)K. The fitting formula was obtained for dose rate conversion factors, enabling them to be conveniently calculated for a room with arbitrary dimensions. For concrete block samples collected in the area of Niš, Serbia, the measurement of the radionuclide activity concentrations was also carried out. The evaluated absorbed dose rate conversion factors were then applied in the assessment of corresponding indoor gamma dose rates, finding that all the concrete samples fulfilled the usage requirement.
本研究测定了作为建筑材料的混凝土中天然放射性核素所致室内空气中的吸收伽马剂量率。利用Harima（几何级数）积累因子，通过点核技术评估了标准房间以及不同尺寸房间中(238)U、(232)Th和(40)K的剂量率转换因子。标准房间的转换因子值（单位：nGy h(-1) (Bq kg(-1))(-1)）分别为：(238)U为0.76、(232)Th为0.91、(40)K为0.070。得到了剂量率转换因子的拟合公式，可方便地计算任意尺寸房间的转换因子。对于在塞尔维亚尼什地区采集的混凝土块样品，还进行了放射性核素活度浓度的测量。然后将评估得到的吸收剂量率转换因子应用于相应室内伽马剂量率的评估，结果表明所有混凝土样品均满足使用要求。
