Alnour I A, Wagiran H, Ibrahim N, Hamzah S, Elias M S, Laili Z, Omar M
Faculty of Science, Department of Physics, Universiti Teknologi Malaysia, 81310 UTM, Skudai, Johor, Malaysia.
Radiat Prot Dosimetry. 2014 Jan;158(2):201-7. doi: 10.1093/rpd/nct206. Epub 2013 Aug 21.
The distribution of natural radionuclides ((238)U, (232)Th and (40)K) and their radiological hazard effect in rocks collected from the state of Johor, Malaysia were determined by gamma spectroscopy using a high-purity germanium detector. The highest values of (238)U, (232)Th and (40)K activity concentrations (67±6, 85±7 and 722±18 Bg kg(-1), respectively) were observed in the granite rock. The lowest concentrations of (238)U and (232)Th (2±0.1 Bq kg(-1) for (238)U and 2±0.1 Bq kg(-1) for (232)Th) were observed in gabbro rock. The lowest concentration of (40)K (45±2 Bq kg(-1)) was detected in sandstone. The radium equivalent activity concentrations for all rock samples investigated were lower than the internationally accepted value of 370 Bq kg(-1). The highest value of radium equivalent in the present study (239±17 Bq kg(-1)) was recorded in the area of granite belonging to an acid intrusive rock geological structure. The absorbed dose rate was found to range from 4 to 112 nGy h(-1). The effective dose ranged from 5 to 138 μSv h(-1). The internal and external hazard index values were given in results lower than unity. The purpose of this study is to provide information related to radioactivity background levels and the effects of radiation on residents in the study area under investigation. Moreover, the relationships between the radioactivity levels in the rocks within the geological structure of the studied area are discussed.
利用高纯锗探测器通过伽马能谱法测定了从马来西亚柔佛州采集的岩石中天然放射性核素（(238)U、(232)Th 和 (40)K）的分布及其放射性危害效应。在花岗岩中观测到(238)U、(232)Th 和 (40)K 活度浓度的最高值（分别为 67±6、85±7 和 722±18 Bq kg(-1)）。在辉长岩中观测到(238)U 和 (232)Th 的最低浓度（(238)U 为 2±0.1 Bq kg(-1)，(232)Th 为 2±0.1 Bq kg(-1)）。在砂岩中检测到(40)K 的最低浓度（45±2 Bq kg(-1)）。所有调查岩石样品的镭当量活度浓度均低于国际公认值 370 Bq kg(-1)。本研究中镭当量的最高值（239±17 Bq kg(-1)）记录在属于酸性侵入岩地质构造的花岗岩区域。发现吸收剂量率范围为 4 至 112 nGy h(-1)。有效剂量范围为 5 至 138 μSv h(-1)。结果给出的内、外危害指数值均低于 1。本研究的目的是提供与研究区域内放射性背景水平以及辐射对居民的影响相关的信息。此外，还讨论了研究区域地质构造内岩石放射性水平之间的关系。
