Research And Implementation Of Temperature Drift Correction Method For Seawater Radioactivity Sensor

Seawater radioactivity environment monitoring is of great significance,which provides valuable data support for the protection of seawater ecological environment,disaster prevention and reduction,emergency decision-making and other work.At present,Na I(Tl)seawater radioactivity sensor is mainly used for in-situ monitoring of seawater radioactivity environment.By analyzing the seawater gamma spectrum measured by the Na I(Tl)seawater radioactivity sensor,the radioactivity level of seawater can be evaluated,and the activity of target nuclides in seawater can be further analyzed.However,due to the temperature effect of the internal component module of Na I(Tl)seawater radioactivity sensor,the ambient temperature will change during storage transportation and in-situ measurement of the sensor,so that the temperature drift of the measured seawater gamma spectrum will occur,thus affecting the accuracy and reliability of the seawater gamma spectrum analytical results.This thesis researches the temperature drift correction method of Na I(Tl)seawater radioactivity sensor based on the analysis of the temperature drift law,and applies it to self-developed Na I(Tl)seawater radioactivity sensor to complete the verification of the temperature drift correction method.Firstly,the temperature drift law of NaI(Tl)seawater radioactivity sensor is researched and analyzed.By designing and carrying out the temperature experiment in air and water environment of Na I(Tl)seawater radioactivity sensor,the gamma spectrum temperature drift law of cooling process and heating process was researched and analyzed,including the qualitative drift law of characteristic peak and the quantitative drift law of peak location,which laid the foundation for the research of temperature drift correction method.Secondly,a temperature drift correction method based on gain adjustment is established.By designing and carrying out the experiment on the relationship between gain of Na I(Tl)seawater radioactivity sensor and peak location,the law between gain and peak location was researched and analyzed.According to the idea of hardware correction method,combined with the temperature drift law of gamma spectrum,a temperature drift correction method based on gain adjustment was established.The method was verified in laboratory air and water environments,and the results showed that the method could effectively correct the temperature drift of Na I(Tl)seawater radioactivity sensor.Thirdly,a temperature drift correction method based on spectrum processing is proposed.Through in-depth research and analysis of the relationship between gamma spectrum drift and temperature change,according to the software correction method,a temperature drift correction method based on spectrum processing is proposed.The method was verified in laboratory air and water environments,and the results showed that the method could effectively correct the temperature drift of Na I(Tl)seawater radioactivity sensor.Finally,a temperature drift correction method combining gain adjustment and spectrum processing is proposed.In view of the actual working scenario of Na I(Tl)seawater radioactive sensor during long-term continuous operation at sea,a temperature drift correction method that is more suitable for practical application of Na I(Tl)seawater radioactivity sensor combined with gain adjustment and spectrum processing was further researched and proposed by effectively combining gain adjustment and spectrum processing correction method.The method was verified in laboratory air and water environments,and the results showed that the method could effectively correct the temperature drift of Na I(Tl)seawater radioactivity sensor.The offshore work site long-term continuous operation experiment of Na I(Tl)seawater radioactivity sensor was designed and carried out to verify the practical application effect of the correction method combined with gain adjustment and spectrum processing.The results show that the method can effectively correct the temperature drift of Na I(Tl)seawater radioactivity sensor in the actual working environment at sea,and improve the accuracy and reliability of the analytical results of seawater radioactivity monitoring data.