Specific activities and radiation hazard parameters calculations of natural radionuclides in AL-Mustansiriyah university soils using NaI(Tl) detector

Nada Farhan Kadhim

doi:10.30723/ijp.v14i30.219

Abstract

The specific activities of the natural radionuclides U-238 and Th-232 and K-40 in 14 soil samples collected from different sites fromAL-Mustansiriyah university at two depths (topsoil "surface" and20cm depth) were be investigated using gamma ray spectrometer3"x3" NaI(Tl) scintillation detector.The analysis of the energy spectra of the soil samples show thatthese samples have specific activities ranging with (16.08-51.11)Bq/kg for U-238, (14.79-52.29) Bq/kg for Th-232 and (191.08-377.64) Bq/kg for K-40, with an average values of 29.37, 34.14 and289.62 Bq/kg for U-238, Th-232, k-40 respectively. The radiationhazard parameters of the natural radionuclides; radium equivalentactivity (Raeq), gamma absorbed dose rate (Dγ), annual effective doserate (Eγ), internal and external hazard index (Hin, Hex) have also beencalculated. The maximum value of specific activities and hazardparameters was found in the sample of the soil gathered from theLiterature college center. All the calculated specific activates valueswere be in the ranges of worldwide averages, and below than theglobal permissible limits, this would indicate that the soils of theUniversity is safety for both students and staff.

Highlights

The analysis of the energy spectra of the soil samples show that these samples have specific activities ranging with (16.08-51.11) Bq/kg for U-238, (14.79-52.29) Bq/kg for Th-232 and (191.08377.64) Bq/kg for K-40, with an average values of 29.37, 34.14 and 289.62 Bq/kg for U-238, Th-232, k-40 respectively
The specific activities calculated for the three natural radionuclides detected in the 14 soil samples have the range of
Since the last three values are lower than unity we can say that the radiation hazards of the studying soil in this region is low and lie within the acceptable limits

Summary

Near the student club

Radioactivity measurements The measurements were based on the recording natural radioactivity quantities of three natural long-lived elements U-238 and K-40 which are considered the photo peaks at (1760,2614keV) and (1460keV) respectively, the concentration of Tl208 and Bi-214 occur in the samples due to disintegration of U-238 and Th-232 respectively, the activities of Tl-208 and Bi-214 in the samples indicates the presence of U-238 and Th-232 respectively. The specific activities of the radionuclides were calculated from the equation [7]: Specific. Where: (Eff.) is the efficiency of specific energy, (Iγ) is the intensity of emitted gamma-ray(%), W: sample weight in (kg),and T: measuring time (s). Efficiency calibration curve The efficiency curve was managed by accumulated the gamma ray spectrum for a mixing of three standard point sources of known activity and different gamma energy peaks, Ba-133(356.1 keV), Cs137(661.9keV) and Co-60(1173.2 and 1332.5keV). The time of accumulated spectrum was (14400s) and the efficiency of each source would be calculated by Eq (1). Hazard Radiation Parameters Radium equivalent (R ), gamma absorbed dose (D ), annual effective dose E ) External Hazard Index ( ) and Internal hazard index Where , and are the specific activities of U-238, Th-232 and K-40 respectively

Results and discussion

Conclusions

Raeq D