Research On Related Technology Of Nuclear Pulse Digital Forming And Pulse Stacking

Nuclear spectrum measurement technology is an important means of obtaining information in nuclear physics research,nuclear technology applications and nuclear signal processing.Nuclear energy spectrometers,as an important tool for nuclear energy spectrum measurement,have been the focus of researchers in the nuclear field for their technical updates and performance enhancements.With the rapid development of computer technology and electronic technology,from the end of the 20 th century,the emergence of digital nuclear spectrometers marks the development of nuclear energy spectrum measurement technology,which will gradually replace the traditional analog nuclear energy spectrometer.Digital nuclear signal processing technology will become the mainstream research direction.The digital pulse shaping of nuclear signals,the identification of pulse stacks,the accumulation of discards and the processing of pulse stacking are key aspects of digital nuclear energy spectrum measurement technology.Although many scientific research institutions and universities at home and abroad have carried out research on it,the proposed pulse stacking identification method is not complete enough,and the probability of pulse stacking has not been studied in depth,which leads to certain inaccuracy in discarding pulse accumulation.It also reduces the measurement accuracy of the entire digital nuclear spectrum measurement system.At present,the most important method for processing pulse stacking is to perform stacking and discarding or stacking retention after pulse stacking.Stacking and discarding will reduce the impact of stacking on nuclear signal processing,but it will also reduce the pulse counts,which will also affect the measurement accuracy of the nuclear spectrometer;retention of pulses of a certain degree of accumulation will have a large impact on the energy resolution of the nuclear spectrometer.If the overlapping pulses can be effectively decomposed and the high resolution accuracy is ensured,the parameters of the overlapping pulses can be effectively extracted without affecting the pulse counting,which is undoubtedly a better pulse stacking processing method.In view of the above technical problems,the paper mainly studies and discusses the key issues related to digital signal forming and pulse stacking.The main work and achievements are as follows:1.Starting from the statistical characteristics and generation methods of nuclear signals,this paper analyzes the statistical characteristics such as counting,time interval and amplitude nuclear signal.In this paper,through the circuit model of the detector,the nuclear signal exponential pulse and the mathematical model of double exponential pulse,the numerical simulation of the exponential pulse with different amplitudes and different attenuation constants is carried out by using MATLAB.In this paper,the digital simulation of different fast forming attenuation constants and different slow forming attenuation constants is performed for the double exponential pulse.2.The Gaussian shaping algorithm based on wavelet technology and S-K filter is discussed in this paper.Gaussian shaping based on S-K filter is more suitable for digital shaping.The S-K digital Gaussian forming of different forming parameters K is performed for exponential pulse and double exponential pulse.The factors affecting S-K digital Gaussian forming are analyzed in this paper.The generation of noise and the filtering of three modes are studied and realized.3.The author analyzes and compares two trapezoidal(triangle)forming algorithms: Z-variation and function convolution.These two algorithms are implemented separately by means of MATLAB platform,and the factors affecting trapezoidal(triangle)forming are deeply studied.At the same time,the author also improved the traditional trapezoidal shaping algorithm.4.The paper respectively proposes identification methods and stack rejection criteria for pulse stacking in S-K Gaussian,trapezoidal,and triangular forming.Combined with the statistical characteristics of the nuclear signal,the paper proposes a pulse stacking probability calculation formula and a stacking discard probability formula,and solves the pulse stacking probability of various cases,and its probability of calculation error is small.5.The genetic algorithm is used to realize the effective decomposition of two overlapping pulses,three overlapping pulses and four overlapping pulses,and the decomposition accuracy is good.The paper also discusses the decomposition ability of the genetic algorithm.The decomposition of the overlapping pulses can accurately extract the amplitude and attenuation constant of the S-K digitized Gaussian pre-exponential pulse,which also proves the decomposability of pulse packing.