Iman Tarik Al-Alawy
*Manar Dhyeaa Salim*
*Al-Mustansiryiah University–Science College–Physics Department
The specific activity of natural radionuclides in (18) soil samples collected from antiquities area of Tello (Girsu) city in Dhi-Qar Governorate (31.0459863N, 46.2534257E) in southern Iraq have been studied and evaluated. Experimental results were obtained by using a gamma ray spectrometer analysis system consists of a scintillation detector Sodium Iodide activated by Thallium NaI(Tl) of (3" × 3") crystal dimension at the laboratory of radiation detection and measurement in Science Collage, University of Kufa. The spectrometer has been calibrated for energy by acquiring a spectrum from four standard sources of gamma radiations supplied by spectrum techniques (LLC). The measuring time of all soil samples is (18000 seconds), it was found that, for Tello (Girsu) city the soil specific activity ranges from (22.68±3.94 to 14.69±2.24) Bq/kg for , from (17.41±2.23 to 11.23±2.34) Bq/kg for and from (346.49±10.68 to 266.96±10.55) Bq/kg for . The results have been compared with the acceptable data of the worldwide literatures. In order to evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity (Raeq), the gamma absorbed dose rate (D), the annual effective dose rate and the both (external and internal) hazard index have been calculated and compared with the acceptable values of the worldwide average (UNSCEAR, 2000).
KEYWORDS: Natural radioactivity; Specific activity; NaI(Tl) detector; Gamma-ray spectrometry; Radium equivalent activity.