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A New Approach for the Determination of Dose Rate and Radioactivity for Detected Gamma Nuclides Using an Environmental Radiation Monitor Based on an NaI(Tl) Detector

Ji, Young-Yong*; Kim, Chang-Jong*; Lim, Kyo-Sun*; Lee, Wanno*; Chang, Hyon-Sock; Chung, Kun Ho*

doi: 10.1097/HP.0000000000000706
Operational Topics

To expand the application of dose rate spectroscopy to the environment, the method using an environmental radiation monitor (ERM) based on a 3" × 3" NaI(Tl) detector was used to perform real-time monitoring of the dose rate and radioactivity for detected gamma nuclides in the ground around an ERM. Full-energy absorption peaks in the energy spectrum for dose rate were first identified to calculate the individual dose rates of 214Bi, 228Ac, 208Tl, and 40K distributed in the ground through interference correction because of the finite energy resolution of the NaI(Tl) detector used in an ERM. The radioactivity of the four natural radionuclides was then calculated from the in situ calibration factor—that is, the dose rate per unit curie—of the used ERM for the geometry of the ground in infinite half-space, which was theoretically estimated by Monte Carlo simulation. By an intercomparison using a portable HPGe and samples taken from the ground around an ERM, this method to calculate the dose rate and radioactivity of four nuclides using an ERM was experimentally verified and finally applied to remotely monitor them in real-time in the area in which the ERM had been installed.

*Environmental Radioactivity Assessment Team, Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea; † SI Detection Co. Ltd., Daejeon 34051, Republic of Korea.

The authors declare no conflicts of interest.

Young-Yong Ji has been working as a senior researcher at Korea Atomic Energy Research Institute (KAERI) since 2004. He is in charge of the gamma-ray spectrometry and environmental radiation survey around nuclear facilities in the environmental radioactivity assessment team of KAERI. He has conducted several projects as a leader, such as studies about environmental radiation survey and analytical evaluation of natural radionuclides in NORM (naturally occurring radioactive materials) and TENORM (technically enhanced NORM). Now, he is interested in the in situ gamma-ray spectrometry in company with the Monte Carlo simulation using the MCNP code. His email is

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