Research On Digital Multi-channel Pulse Amplitude Analyzer Based On FPGA And Preliminary Development Of Digital Gamma Spectrometer

Nuclear power spectrum measurement technology is playing an increasingly important role in the basic research of nuclear science and many application fields. Multi channel pulse amplitude analyzer is the key component of nuclear power spectrum measurement system,and its performance directly affects the accuracy and accuracy of energy spectrum measurement. The digital multichannel pulse amplitude analyzer has a filter forming flexible, strong antiinterference ability, processing speed and other advantages, the digital multi-channel pulse amplitude analyzer has become an important direction of the development of the nuclear sp-ectrum measurement instrument.With the rapid development of high-speed ADC devices, programmable gate array semiconductor technology, it has become an important research topic to improve the digital multichannel pulse amplitude analyzer technology performance index. In order to realize the optimization and technical performance of the nuclear spectrum measurement system, it focuses on the development of the technology of digital multi-channel pulse amplitude analyzer based on FPGA in this paper.A digital multi-channel pulse analyzer is designed to take the high-speed ADC+FPGAhardware structure. This paper focuses on the circuit design of high-speed ADC sampling, FPGA system, STM32 microcontroller and its peripheral system. Including: it achieves high-speed digital processing of nuclear pulse signal to be FPGA’s Altera chip(the EP4CE6E22C8 model) as the core processor of the system. it makes the useful information as much as possible to retain nuclear pulse signal to use AD9215 chip with the 100 MHz sampling rate. Through the design of STM32 circuit, the communicateon between multi channel pulse analyzer and the upper computer is realized. On the whole, the hardware system designed in this paper has the characteristics of high integ- ration, strong parallel computing ability and so on.It designed the software system of the digital multi-channel pulse analyzer to use the internal logic function of FPGA module and Verilog HDL language in this paper. Based on introduce the STM32 processor programming knowledge, this paper emphatically introduces the nuclear pulse signal processing forming, accumulation of discrimination, Gauss peak extraction and line generating module; In addition, it is designed a spectrum processing software on PC to base on introducing the basic knowledge of Visual Studio 2010 programming.It is constructed a digital spectrum measurement system(prototype) to base on the hardware system of digital multi-channel pulse analyzer and the software of the host computer in this paper. It is constructed the test platform of the energy spectrum measurement system that the cesium source(137Cs) as a gamma ray source, the NaI(Na I) detector to measure the gamma ray spectrum. They were tested energy resolution and system stability of the energy spectrum measurement system. From the preliminary test data, the system has a good digital capability, and its comprehensive performance indicators have reached the design requirements of the graduation thesis.