Research And Implementation Of FPGA-based Digital Multi-channel Pulse Amplitude Analysis System

Digital multi-channel pulse amplitude analysis technology is an important part of the development of nuclear energy spectrum measurement instruments.Based on the National Natural Science Foundation of China（NSFC）project,the research and design implementation of pulse stacking processing algorithm is carried out to address the problem that pulse stacking causes the degradation of count rate and resolution of measurement results in digital multi-channel pulse amplitude analysis system.The related research contents and results are as follows.（1）The design principle of digital multi-channel pulse amplitude analysis system is investigated,and the triangular-trapezoidal hybrid filter-forming algorithm is proposed for the key pulse stacking problem by combining the better peak localization and stacking discriminative ability of the triangular filter-forming algorithm with the stable pulse peak extraction ability of the trapezoidal filter-forming algorithm.The simulation model verifies that the algorithm has the largest peak energy spectrum count rate and the best energy spectrum resolution compared with the results of the trapezoidal filter-forming algorithm,the triple trapezoidal-forming algorithm and the pulse width discrimination method.（2）A digital multi-channel pulse amplitude analysis system is designed and implemented based on FPGA.The Zynq-7000 XC7Z020-2CLG40 I FPGA chip from Xilinx is selected as the core,and the high-speed AD9238 chip is used to acquire the nuclear pulse signals generated by the detector and the preamplifier circuit,and the System Generator digital signal processing development tool is used to complete the design and implementation of the digital signal processing algorithm module.work.（3）Build a digital multi-channel pulse amplitude analysis system measurement platform,the actual measurement of stainless steel,brass,soil three national standard samples.The test results show that the average deviation of the system is 0.45% and the maximum deviation of the pulse amplitude is 0.0162 V.The comparison experiments on stainless steel samples show that the peak count rate of the energy spectrum generated by the triangle-trapezoid hybrid filter-forming algorithm and the trapezoid filter-forming algorithm are 12841 cps and 5592 cps,respectively.The resolution is 6.80% and 7.76%respectively,and the algorithm proposed has improved the performance of both energy spectrum count rate and resolution.In summary,the hybrid triangular-trapezoidal filtering and shaping algorithm proposed provides an innovative method for pulse stacking problem processing.The basic performance and practical operation of the FPGA-based digital multichannel pulse amplitude analysis system are good,which meets the design objectives and has practical application value.