[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Evaluation of Uncertainty Measurement of Radionuclides Minimum Detectable Activity in Large Plastic Scinllators

摘要： This work is devoted to the evaluation of the measurement uncertainty of minimum detectable activity (MDA) for 137Cs on its gamma radiation with large plastic scintillators (PS) used in the portal monitors (PM). The influence of scintillators volume and irradiation geometry on the MDA evaluation of the measurement uncertainty was studied. It is shown that the estimated expanded MDA measurement uncertainty interval on 137Cs is 21—23 per cent. The absolute value of the MDA measurement uncertainty when changing geometry of irradiation increases 10 times. Change in the volumes of the examined PS causes a change of MDA measurement uncertainty within 10 per cent.