Uosif M A M, Abdel-Salam L M
Department of Physics Department, Faculty of Sciences, Al-Azhar University, Assiut, Egypt.
Radiat Prot Dosimetry. 2011 Nov;147(3):467-73. doi: 10.1093/rpd/ncq448. Epub 2010 Dec 4.
The contents of natural radionuclides ((226)Ra, (232)Th and (40)K) were measured in investigated samples (granite Gabal Ras Barud, Eastern Desert in Egypt) by using gamma spectrometry (NaI (Tl) 3″×3″). The activities of (226)Ra, (232)Th series and (40)K are between (3.8±0.5 and 172.8±1135.1±56.8 8.6), (2.3±0.3 and 103.8±5.2) and (53.1±2.7 and 1135.1±56.8) Bq kg(-1), respectively. With average total annual dose being only 67.2 μSv y(-1), this value is about 6.72 % of the 1.0 mSv y(-1) recommended by the International Commission on Radiological Protection (ICRP-60, 1990) as the maximum annual dose to members of the public. Geochemical studies revealed that Gabal Ras Barud is formed from a highly fractionated biotite granite, with SiO(2) >75 % and generally enriched in alkali with K/Na >8 %.
采用γ能谱法（碘化钠（铊）3″×3″）对调查样本（埃及东部沙漠的加巴尔拉斯巴鲁德花岗岩）中的天然放射性核素（（226）镭、（232）钍和（40）钾）含量进行了测量。（226）镭、（232）钍系和（40）钾的活度分别在（3.8±0.5和172.8±1135.1±56.8 8.6）、（2.3±0.3和103.8±5.2）以及（53.1±2.7和1135.1±56.8）贝克勒尔每千克（Bq kg⁻¹）之间。年平均总剂量仅为67.2微希沃特每年（μSv y⁻¹），该值约为国际放射防护委员会（ICRP - 60，1990）推荐的公众成员最大年剂量1.0毫希沃特每年（mSv y⁻¹）的6.72%。地球化学研究表明，加巴尔拉斯巴鲁德由高度分异的黑云母花岗岩形成，二氧化硅（SiO₂）含量>75%，通常富含碱金属，钾/钠>8%。
