Radioactive source strength effect on gamma radiation monitoring with a NaI (Tl) scintillation detector

Abstract

The accurate monitoring of gamma radiation doses in the environment has become essential due to its effect on human health. In this study, the temperature dependence of NaI (Tl) scintillation detectors based on the daily/annually measured dose rate in the environment as well as the importance of selecting the appropriate radioactive source strength when calibrating NaI (Tl) detectors for gamma radiation monitoring were investigated. The temperature correction coefficients discovered during the calibration of the BDKG-03 detector by Atomtex were verified, and whether the time duration of the measurement interval has an effect on readings of gamma radiation was also investigated in the city of Tomsk. NaI (Tl) scintillation detectors were used to monitor the gamma background radiation in the environment. The detectors were calibrated with both high and low radioactive sources to obtain a temperature correction coefficient in order to stabilize the influence of temperature change on the detector at different time intervals. This was used to study the correlation between the daily and annual dose rates of low gamma background radiation. The results showed that there was a shift in the spectrum of the daily and annual dose rates calculated using the algorithm obtained when the detector was calibrated with a highly radioactive source to the position of the constant coefficient for low-level dose. However, the ones obtained when the detector was calibrated with a low radioactive source and that of the constant coefficient for a low-level dose overlapped each other. This demonstrated that the type of radioactive source used in detector calibration during manufacture has an effect on the temperature correction coefficient, which in turn has an effect on the accuracy of the ambient dose rate when used to monitor gamma radiation. The duration of the time interval for measurement was found to be very important since it has an effect on dose rate readings.