Rahman S U, Faheem M, Anwar J, Ziafat M, Nasir T
Department of Physics, COMSATS Institute of Information Technology, Islamabad, Pakistan.
J Radiol Prot. 2009 Dec;29(4):499-505. doi: 10.1088/0952-4746/29/4/004. Epub 2009 Nov 18.
It is a well known fact that natural radionuclides are the major contributors towards the gamma ray exposure received by the general public. In this context, soil samples were collected from the Islamabad capital territory and activities due to (226)Ra, (232)Th, (40)K and (137)Cs were measured using gamma ray spectrometry: activities ranged from 41.5-106.2 Bq kg(-1), 4.0-193.8 Bq kg(-1), 325.3-657.4 Bq kg(-1) and 1.6-9.45 Bq kg(-1), respectively. From the measured activities, the external hazard index, internal hazard index, absorbed dose rate and mean annual effective dose were calculated. External and internal hazard indices were calculated as 0.76 and 0.95, respectively. The mean absorbed dose rate was found to be 130.97 nGy h(-1). The mean effective dose was estimated as 0.16 mSv y(-1), which is less than the maximum permissible dose of 1 mSv y(-1).
天然放射性核素是公众所接受的伽马射线照射的主要来源，这是一个众所周知的事实。在此背景下，从伊斯兰堡首都地区采集了土壤样本，并使用伽马射线能谱法测量了由（226）镭、（232）钍、（40）钾和（137）铯产生的活度：活度范围分别为41.5 - 106.2贝克勒尔每千克、4.0 - 193.8贝克勒尔每千克、325.3 - 657.4贝克勒尔每千克和1.6 - 9.45贝克勒尔每千克。根据测量的活度，计算了外照射危害指数、内照射危害指数、吸收剂量率和年平均有效剂量。外照射和内照射危害指数分别计算为0.76和0.95。发现平均吸收剂量率为130.97纳戈瑞每小时。估计平均有效剂量为0.16毫希沃特每年，低于最大允许剂量1毫希沃特每年。
