Research And Performance Analysis Of Digital Shaping Of Nuclear Pulse Signals

As one of the most important research methods in nuclear physics and particle physics,the measurement and analysis of nuclear energy spectrum has always been a hot topic in the field of nuclear electronics.The traditional filter shaping technology in analog circuits is deficient in noise suppression and baseline recovery.Too many hardware circuits also lead to low system stability.With the development of digital components such as high-speed integrated circuits,high-resolution,high-speed sampling ADC and digital signal processor,the digital processing technology of nuclear pulse signal has gradually become a hot research issue in the design of nuclear spectrometer system.On the basis of investigating the development history and research status of digital shaping theory and algorithm at home and abroad,this paper analyses the main factors of energy resolution of digital nuclear spectrometer measurement system,and chooses digital trapezoidal shaping,triangular shaping and Gaussian shaping of nuclear pulse signal as the main research objects.The design and implementation of digital shaping method for nuclear pulse signal are studied in this paper.The following results are obtained:?1?The numerical recurrence models of different digital shaping algorithms are deduced and established.The transfer function of digital trapezoidal?triangle?forming algorithm is deduced by Z transform method and function convolution method.The Sallen-Key and CR-?RC?^m circuits are analyzed by Kirchhoff current law,and the numerical recurrence model of Gauss forming is established.?2?Digital shaping under different recursive models is realized.Based on the platform of MATLAB,the numerical recurrence models are constructed,and the digital shaping processing of simulated nuclear signals and actual sampled nuclear signals is completed.The shaping results under different shaping schemes and parameters are analyzed and evaluated.According to the comprehensive characteristics of peak area and energy resolution obtained by different digital shaping models,the optimal digital shaping scheme and the basis for selecting shaping parameters were obtained,and the correctness and rationality of the numerical models were verified.?3?The performance of digital filtering shaping algorithm is evaluated.Amplitude-frequency response function in frequency domain is obtained by Fourier transform of recurrence function in Z domain,and the filtering effect of each algorithm under different shaping parameters is studied.For ¹³⁷Cs gamma-ray and ⁵⁵Fe characteristic X-ray collected at 20MHz sampling frequency,the same shaping parameters and different shaping parameters of the same shaping scheme are adopted to perform the performance analysis.Finally,the peak area and energy resolution of each shaping scheme are obtained.Based on the above research results,it is shown that the digital shaping model can effectively realize the shaping processing of nuclear pulse signals.The triangular shaping has better peak area,the Gauss shaping has better energy resolution,and the trapezoidal shaping takes into account both energy resolution and peak area by synthetically analyzing the energy spectrum information obtained under different shaping schemes and shaping parameters.The optimal shaping scheme and parameters obtained can provide some reference for the follow-up research in this field and the digitization of nuclear instruments.