Monte Carlo simulation of NaI(Tl) detector for in situ radioactivity measurements in soil

NaI(TI) detectors are the most universally used scintillation detectors for radionuclides measurements in soil. The measured concentrations are used for dose estimation to human population. Prior to dose assessment and risk estimation associated with radiation levels, it is very crucial to perform uncertainty analysis as part of quality assurance. In the present study, an attempt was made to increase the confidence of the spectral analysis and produce more reliable results in the concentration of low level radionuclides in environment using MCNP simulations with the help of IAEA certified soil standards. The complete detector setup is modelled in MCNP and gamma spectrum is computed. The result shows that primordial radionuclides activities obtained with spectrometric measurements are in good agreement with corresponding reported activities. The simulated and experimental activities are compared. The uncertainty analyses of measurements are within the 95 % confidence interval which concludes that the detector is performing well, and it is suitable for radionuclides measurements