Study on Influence of Suspended Particulate Matter in Water Body Online γ Energy Spectrum Measurement

With the expansion of the nuclear energy scale and the wide application of non-power nuclear technology in China, the online γ energy spectrum measurement of inland storage water bodies has become an important monitoring technology to ensure public radiation safety. However, the change in the water body environment seriously affects the accuracy of online γ energy spectrum measurement results in the water body. In this study, the suspended particles in water are studied through Monte Carlo simulation and physical experiments, and the effects of non-radioactive suspended particles and radioactive suspended particles on the corresponding detection efficiency of radionuclides are analyzed. The results show that the non-radioactive suspended particles have little effect on the detection efficiency of the water body online γ energy spectrum measurement system in a certain turbidity range (under normal environment), and there is no need for turbidity correction. For radioactive suspended particles, the interference of radioactive suspended particles on the measurement results of 40K, 238U, and 226Ra gradually increases with the increase of water body turbidity. At the same time, a correction method for the influence of water body turbidity of radioactive suspended particulate matter is proposed based on the linear relationship between turbidity and nuclide content in suspended particulate matter. Using the turbidity activity concentration correction to treat 40K nuclides, the relative error of the correction value is less than 1.6%, which realizes the correction of the influence of water turbidity, and further improves the online accuracy of the water body online γ energy spectrum measurement system.