In the design of filter shaping circuits for nuclear pulse signals,inverting filter shaping circuits perform better than non-inverting filter shaping circuits.Because these circuits facilitate changing the phase of a ...In the design of filter shaping circuits for nuclear pulse signals,inverting filter shaping circuits perform better than non-inverting filter shaping circuits.Because these circuits facilitate changing the phase of a pulse signal,they are widely used in processing nuclear pulse signals.In this study,the transfer functions of four types of inverting filter shaping circuits,namely the common inverting filter shaping,improved inverting filter shaping,multiple feedback low-pass filter shaping,and third-order multiple feedback low-pass filter shaping,in the Laplacian domain,are derived.We establish the numerical recursive function models and digitalize the four circuits,obtain the transfer functions in the Z domain,and analyze the filter performance and amplitude-frequency response characteristics in the frequency domain.Based on the actual nuclear pulse signal of the Si-PIN detector,we realize four types of inverting digital shaping.The results show that under the same shaping parameters,the common inverting digital shaping has better amplitude extraction characteristics,the third-order multiple feedback low-pass digital shaping has better noise suppression performance,and the multiple feedback digital shaping takes into account both pulse amplitude extraction and noise suppression performance.展开更多
A principle and method of constructing the digital acquisition system is presented in this work,which is convenient for the study on the theories and algorithms of digital nuclear signal processing.The hardware system...A principle and method of constructing the digital acquisition system is presented in this work,which is convenient for the study on the theories and algorithms of digital nuclear signal processing.The hardware system of the digital acquisition system consists of front-end controller,waveform digitizer and PC workstation,on which the software system has been developed based on Visual C++under Windows environment.The alterable-frequency sampling(AFS)algorithm and the alterable-frequency trapezoidal filter(AFTF)algorithm have also been studied in the real-time environment,along with a digital nuclear spectrum acquisition system being set up based on the new algorithms and theγ-ray spectra of 241Am being shown.A useful experimental platform could be provided by this work for the successive work such as the development of global digitized nuclear measurement system and the study of digital nuclear signal processing.展开更多
CR–RCm filters are widely used in nuclear energy spectrum measurement systems. The choice of parameters of a CR–RCm digital filter directly affects its performance in terms of energy resolution and pulse count rate ...CR–RCm filters are widely used in nuclear energy spectrum measurement systems. The choice of parameters of a CR–RCm digital filter directly affects its performance in terms of energy resolution and pulse count rate in digital nuclear spectrometer systems. A numerical recursive model of a CR differential circuit and RC integration circuit is derived, which shows that the shaping result of CR–RCm is determined by the adjustment parameter (k, it determines the shaping time of the shaper) and the integral number (m). Furthermore, the amplitude– frequency response of CR–RC^m is analyzed, which shows that it is a bandpass filter;the larger the shaping parameters (k and m), the narrower is the frequency band. CR–RC^m digital Gaussian shaping is performed on the actual sampled nuclear pulse signal under different shaping parameters. The energy spectrum of 137Cs is measured based on the LaBr3(Ce) detector under different parameters. The results show that the larger the shaping parameters (m and k), the closer the shaping result is to Gaussian shape, the wider is the shaped pulse, the higher is the energy resolution, and the lower is the pulse count rate. For the same batch of pulse signals, the energy resolution is increased from 3.8 to 3.5%, and the full energy peak area is reduced from 7815 to 6503. Thus, the optimal shaping parameters are m -3 and k -0.95. These research results can provide a design reference for the development of digital nuclear spectrometer measurement systems.展开更多
In this paper, we present a novel method for digital nuclear signal processing based on image processing and recognition, which can improve signal-to-noise ratio of digital nuclear signal effectively without changing ...In this paper, we present a novel method for digital nuclear signal processing based on image processing and recognition, which can improve signal-to-noise ratio of digital nuclear signal effectively without changing the signal shape. The digital nuclear signal with a "time-amplitude" series is converted into a grayscale image with adjustable pixel size. Template of the converted image is extracted by means of modern image processing methods, such as spatial digital low-pass filtering, image binary and the skeleton extracting of images. The needed parameters are extracted from the template image. The method of template extracting presented in this paper can be used flexibly to extract template of nuclear signals, whether the whole or even part of that, and got multi templates corresponding to the whole or partial characters of the signals. The results of image processing,along with γ-ray energy spectrum of241 Am acquired by this method, show that the new method provides a way to develop future digital nuclear instruments of high efficiency and flexibility, high density and multi parameters.展开更多
描述了一种基于现场可编程逻辑阵列(FPGA)的高速核信号采集系统的设计方案。FPGA作为控制核心,实现对高速Analog-to-Digital Converter(ADC)和Universal Serial Bus(USB)的逻辑控制和数字信号的采样、滤波、甄别、存储、传输处理,并使...描述了一种基于现场可编程逻辑阵列(FPGA)的高速核信号采集系统的设计方案。FPGA作为控制核心,实现对高速Analog-to-Digital Converter(ADC)和Universal Serial Bus(USB)的逻辑控制和数字信号的采样、滤波、甄别、存储、传输处理,并使用异步First In First Out(FIFO)实现ADC数据采集模块和USB数据传输模块2个不同时钟域之间的数据传输,提高数据的吞吐率。最后利用上位机软件进行数据处理和绘图显示。测试结果表明,该系统能够实现核信号的实时、高效采集。展开更多
基金supported by the National Key R&D Project(No.2017YFF0106503)National Natural Science Foundation of China(Nos.11665001 and 41864007)。
文摘In the design of filter shaping circuits for nuclear pulse signals,inverting filter shaping circuits perform better than non-inverting filter shaping circuits.Because these circuits facilitate changing the phase of a pulse signal,they are widely used in processing nuclear pulse signals.In this study,the transfer functions of four types of inverting filter shaping circuits,namely the common inverting filter shaping,improved inverting filter shaping,multiple feedback low-pass filter shaping,and third-order multiple feedback low-pass filter shaping,in the Laplacian domain,are derived.We establish the numerical recursive function models and digitalize the four circuits,obtain the transfer functions in the Z domain,and analyze the filter performance and amplitude-frequency response characteristics in the frequency domain.Based on the actual nuclear pulse signal of the Si-PIN detector,we realize four types of inverting digital shaping.The results show that under the same shaping parameters,the common inverting digital shaping has better amplitude extraction characteristics,the third-order multiple feedback low-pass digital shaping has better noise suppression performance,and the multiple feedback digital shaping takes into account both pulse amplitude extraction and noise suppression performance.
基金Supported by National Natural Science Foundation of China(NSFC)projects(No.1075111)
文摘A principle and method of constructing the digital acquisition system is presented in this work,which is convenient for the study on the theories and algorithms of digital nuclear signal processing.The hardware system of the digital acquisition system consists of front-end controller,waveform digitizer and PC workstation,on which the software system has been developed based on Visual C++under Windows environment.The alterable-frequency sampling(AFS)algorithm and the alterable-frequency trapezoidal filter(AFTF)algorithm have also been studied in the real-time environment,along with a digital nuclear spectrum acquisition system being set up based on the new algorithms and theγ-ray spectra of 241Am being shown.A useful experimental platform could be provided by this work for the successive work such as the development of global digitized nuclear measurement system and the study of digital nuclear signal processing.
基金supported by National Natural Science Foundation of China(Nos.11665001,41864007)National Key R&D Project(No.2017YFF0106503)+1 种基金China Scholarship Council(No.201708360170)One Hundred People Sail in Jiangxi Province,Open-ended Foundation from the Chinese Engineering Research Center(No.HJSJYB2014-03)
文摘CR–RCm filters are widely used in nuclear energy spectrum measurement systems. The choice of parameters of a CR–RCm digital filter directly affects its performance in terms of energy resolution and pulse count rate in digital nuclear spectrometer systems. A numerical recursive model of a CR differential circuit and RC integration circuit is derived, which shows that the shaping result of CR–RCm is determined by the adjustment parameter (k, it determines the shaping time of the shaper) and the integral number (m). Furthermore, the amplitude– frequency response of CR–RC^m is analyzed, which shows that it is a bandpass filter;the larger the shaping parameters (k and m), the narrower is the frequency band. CR–RC^m digital Gaussian shaping is performed on the actual sampled nuclear pulse signal under different shaping parameters. The energy spectrum of 137Cs is measured based on the LaBr3(Ce) detector under different parameters. The results show that the larger the shaping parameters (m and k), the closer the shaping result is to Gaussian shape, the wider is the shaped pulse, the higher is the energy resolution, and the lower is the pulse count rate. For the same batch of pulse signals, the energy resolution is increased from 3.8 to 3.5%, and the full energy peak area is reduced from 7815 to 6503. Thus, the optimal shaping parameters are m -3 and k -0.95. These research results can provide a design reference for the development of digital nuclear spectrometer measurement systems.
基金Supported by National Natural Science Foundation of China(No.11075111)
文摘In this paper, we present a novel method for digital nuclear signal processing based on image processing and recognition, which can improve signal-to-noise ratio of digital nuclear signal effectively without changing the signal shape. The digital nuclear signal with a "time-amplitude" series is converted into a grayscale image with adjustable pixel size. Template of the converted image is extracted by means of modern image processing methods, such as spatial digital low-pass filtering, image binary and the skeleton extracting of images. The needed parameters are extracted from the template image. The method of template extracting presented in this paper can be used flexibly to extract template of nuclear signals, whether the whole or even part of that, and got multi templates corresponding to the whole or partial characters of the signals. The results of image processing,along with γ-ray energy spectrum of241 Am acquired by this method, show that the new method provides a way to develop future digital nuclear instruments of high efficiency and flexibility, high density and multi parameters.
文摘描述了一种基于现场可编程逻辑阵列(FPGA)的高速核信号采集系统的设计方案。FPGA作为控制核心,实现对高速Analog-to-Digital Converter(ADC)和Universal Serial Bus(USB)的逻辑控制和数字信号的采样、滤波、甄别、存储、传输处理,并使用异步First In First Out(FIFO)实现ADC数据采集模块和USB数据传输模块2个不同时钟域之间的数据传输,提高数据的吞吐率。最后利用上位机软件进行数据处理和绘图显示。测试结果表明,该系统能够实现核信号的实时、高效采集。
