Design Of TGS Automatic Detection Software For Nuclear Waste Barrel Based On NaI Detector Array

With the vigorous development of nuclear energy and nuclear technology in China,the demand for the detection of medium and low-level radioactive barreled solid nuclear waste has gradually increased.Tomographic gamma scanning(TGS)is more accurate than Segmented gamma scanning(SGS).It can analysis nuclide species,activity and activity distribution of non-uniformly distributed high-density barreled nuclear waste samples.However,the traditional TGS system based on a single detector has low scanning efficiency.The scanning method based on the detector array can significantly improve the detection efficiency.This paper conducts research on the automatic control and data analysis methods of detector array TGS detection,and develops a TGS automatic detection software system based on the detector array detection platform,which provides important support for the development of the entire system.The main research contents and results are as follows:(1)According to the principle of TGS technology,a nuclear waste barrel TGS automatic detection system is constructed based on the NaI detector array.The mechanical control module composed of the PLC and mechanical device independently developed by the team.The multi-channel acquisition card and NaI detector array are combined to acquire nuclear pulses at multiple measurement positions at once.(2)In order to increase the speed of nuclear pulse peak detection and reduce the error caused by overlapping pulses.By analyzing the amplitude and time width characteristics of the nuclear pulses collected by the system,the traditional single-threshold peak detection method is improved and its feasibility and rationality are verified.The improved single-threshold method can avoid the influence of the fluctuation of the sampling point of the pulse falling edge because the threshold rises with the amplitude in a cycle,and the processing speed is faster than the traditional single-threshold method.By counting the pulse width distribution in the input range,adding pulse width discrimination conditions to the peak detection method to filter overlapping pulses to reduce the peak detection error.(3)The detection control process is designed,and the mechanical control and TGS automatic detection of the constructed automatic detection system are realized.Based on the control interface provided by the acquisition card,the data acquisition function is expanded to flexibly control the acquisition parameters and processes,and the nuclear pulse signal output by the detector array can be collected with high efficiency.On the basis of pulse spectroscopy,the center-of-gravity method is used to smooth the energy spectrum,the first derivative method is used to find the peak,and the Korver method is used to calculate the peak area.The system energy calibration is completed and the complete spectrum data processing process is realized.(4)The accuracy and reliability of the acquisition parameters,mechanical control functions,and spectral data processing of the automatic detection software were tested,and the acquisition parameters with the best spectrum formation effect and acquisition efficiency were determined.The test results show that the operation of each module of the system issafe and reliable,and the error between the spectral data processing results and the GammaVision software analysis results is small.In summary,this paper has conducted in-depth research on the automatic control and data analysis methods of detector array TGS detection,and designed the detector array TGS detection automatic control process and software system.And for the problem of nuclear pulse peak detection,the single-threshold peak real-time extraction method has been improved to improve the peak detection efficiency.The complete ? energy spectrum data processing method and process are realized,and the test of the detector array TGS automatic detection system software is completed.The research of the thesis realizes the cooperative operation of mechanical control of detector array TGS detection,multi-channel nuclear pulse signal acquisition and analysis,and energy spectrum data processing.It is of great significance to improve TGS detection efficiency,promote the application of TGS technology,and realize the independent research and development of TGS devices.