Amin Rafat M, Mansy M, Eissa M F, Eissa H M, Shahin F M
Faculty of Science, Physics Department, Beni Suef University, Egypt.
J Radiol Prot. 2008 Jun;28(2):213-22. doi: 10.1088/0952-4746/28/2/005. Epub 2008 May 22.
Activity concentrations of 238U, 232Th and 40K in rocks and soil samples collected from Sannur cave, Beni Suef governorate, eastern desert of Egypt, were determined using the high-resolution gamma spectrometry technique. The results show that the concentrations of the naturally occurring radionuclides are the following: 238U ranged from 8.51 +/- 1.23 to 20.66 +/- 2.12 Bq kg(-1), 232Th ranged from 7.69 +/- 1.02 to 22.73 +/- 1.60 Bq kg(-1) and 40K ranged from 185.74 +/- 0.42 to 2084.70 +/- 23.30 Bq kg(-1). The radium equivalent activity (Raeq), the absorbed dose rate (D), and the external hazard index (Hex) were also calculated and compared to the international recommended values. The radon concentration and radon exhalation rate from the rock and soil samples were measured using the Can technique. The average value of annual effective dose for cave workers is 1.98 mSv y(-1), while for visitors it is 2.4 microSv per visit. The radon exhalation rate varies from 0.21 +/- 0.03 to 1.28 +/- 0.02 Bq m(-2) h(-1). A positive correlation has been observed between uranium content and radon exhalation rate.
采用高分辨率伽马能谱技术测定了从埃及东部沙漠贝尼苏韦夫省桑努尔洞穴采集的岩石和土壤样品中238U、232Th和40K的活度浓度。结果表明，天然存在的放射性核素浓度如下：238U的范围为8.51±1.23至20.66±2.12 Bq kg-1，232Th的范围为7.69±1.02至22.73±1.60 Bq kg-1，40K的范围为185.74±0.42至2084.70±23.30 Bq kg-1。还计算了镭当量活度（Raeq）、吸收剂量率（D）和外照射危害指数（Hex），并与国际推荐值进行了比较。采用Can技术测量了岩石和土壤样品中的氡浓度和氡析出率。洞穴工作人员的年有效剂量平均值为1.98 mSv y-1，而游客每次访问的有效剂量为2.4 μSv。氡析出率在0.21±0.03至1.28±0.02 Bq m-2 h-1之间变化。已观察到铀含量与氡析出率之间存在正相关。
