Research On The Processing And Analysis Method Of Gamma Spectrum In Seawater Radioactivity Measurement

The research on continuous and automatic monitoring technology for radioactivity in the marine environment is crucial for the safety monitoring of the marine environment.The seawater radioactivity detection technology based on NaI(Tl)sensors has become a core technology for international research and application due to its advantages of high detection efficiency,low cost,low power consumption,and strong environmental adaptability.However,the detection energy resolution of NaI(Tl)sensors is not high enough,and the complex ocean environment makes it difficult to directly identify the types of radioactive nuclides and measure their activity in seawater.Therefore,this article focuses on the difficult problem of complex gamma ray spectrum analysis in seawater.Through theoretical derivation,simulation,and experimental measurement,based on the self-developed seawater NaI(Tl)sensor,in-depth research is conducted on the sensor detection energy spectrum mechanism and gamma spectrum analysis methods.Firstly,conduct research on the processing and analysis method of seawater gamma spectroscopy based on forward analysis.The seawater gamma spectrum processing and analysis method based on forward analysis established in this article uses Savitzky-Golay(S-G)filtering method to smooth the energy spectrum,morphological top hat algorithm to peak the energy spectrum,function fitting method to fit the energy spectrum,and calculate the activity of the target nuclide.The simulation experiment results show that the analytical results of this method are accurate.Forward analysis and calculation are relatively simple.However,the key issue of multiple calculation steps and low resolution cannot be improved,and analysis is only focused on local areas of the energy spectrum,which cannot be extended to full spectrum analysis,making it easy to lose effective information.Secondly,in order to solve the problem of insufficient energy resolution of NaI(Tl)sensors and achieve accurate analysis of energy spectra,research was conducted on the processing and analysis method of seawater gamma spectrum based on inversion analysis.The inversion analysis method models the measurement process of seawater radioactive nuclides from the perspective of signal system;The Gaussian function method is used to establish the detection response matrix of seawater NaI(Tl)radioactive sensor;Propose a Boosted-Gold deconvolution method based on quantitative relationship correction for calculating energy spectra.The simulation experimental results show that compared to forward analysis methods,the inversion analysis method can recover the original radiation information,solve the problem of insufficient energy resolution of NaI(Tl)sensors,and achieve accurate analysis of the entire spectrum.Finally,conduct on-site experiments.This article designs and conducts water tank experiments and on-site seawater measurement experiments to fully verify the accuracy and reliability of energy spectrum processing and analysis methods.The experimental results show that the seawater gamma spectrum processing and analysis method based on inversion analysis can effectively solve the problem of insufficient detection resolution of NaI(Tl)radioactive sensors,and the accuracy of qualitative and quantitative analysis results of nuclides is high,which can meet the needs of seawater radioactive monitoring.It can be practically applied to automatic monitoring of marine radioactive environment safety.