Design Of Digit Almultichannel Pulse Analyzer Based On FPGA

With the improvement of nuclear technology,nuclear spectrum measurement technology is more and more used in many fields such as nuclear power plant safety detection and nuclear science basic research.Multichannel pulse analyzer is one of the important parts of the energy spectrum analyzer.With the rapid development of ADC devices and FPGA chips,digital pulse analyzer gradually replaces the traditional analog pulse multichannel analyzer.In recent years,the development of portable energy spectrometer technology abroad has been mature and commercialized.However,the domestic research and development of multichannel analyzers suitable for field detection spectrometer is still insufficient.In this paper,how to improve the performance of digital pulse multichannel analyzer and expand its application range is studied.In the system,a 1.5 × 1.5 LaBr3(CE)crystal detector is used as the detector of the digital multichannel analyzer.The detector module is composed of photomultiplier tube and high voltage tube holder to generate nuclear pulse signal.The hardware circuit of multichannel analyzer mainly includes five parts: signal conditioning circuit,high voltage circuit,power conversion circuit,AD conversion circuit,FPGA configuration circuit.Using the 10M50SCE144A7 G chip of Altera max series as the main control chip.The ADC chip adopts max12555 chip of Maxim company,with sampling frequency up to 95 MHz.The highly integrated hardware structure meets the needs of portability and digitalization of digital multichannel analyzer.The development environment of FPGA logic configuration is quartus prime,and the hardware description language is Verilog HDL.With the help of Modelsim simulation,serial debugging assistant,signaltap II and other software,FPGA internal logic design is finally completed.This paper introduces the design of peak value extraction,energy spectrum data storage,serial communication and other functional modules.In addition,this paper also introduces the use of C# to write energy spectrum display software.Finally,build a test platform and a digital energy spectrum test system.Two kinds of radioactive sources,Co60 and Cs137,are tested to verify that the energy resolution,stability and Energy Linearity of the digital multichannel analyzer meet the design requirements.