Design And Performance Of An Wide-Range Real-Time Nfm System Using Higher Order Campbell Mode

This paper reports the design of a neutron flux monitor (NFM) system based on field-programmable gate array (FPGA) with a temporal resolution of 1 ms, and a faster time response of 0.2 ms. Notably, the NFM system completes the automatic calibration of the Campbell algorithm based on the least square method of relative error and obtains the real-time neutron count rate with a wide measurement range of 10(9) cps. Simultaneously, higher-order Campbell algorithms (HOC) are proposed and the performance is investigated. Inevitably, simulated neutron pulse waveforms with known pulse counting were utilized to assess the performance of the HOC algorithms. Furthermore, an FPGA-based high-speed neutron pulse signal generator capable of generating different count rates is designed to study the HOC algorithms and verify the reliability of the NFM system. Combining the results of simulation and actual testing, we optimized the counting algorithm at a low count rate, the Campbell algorithm at a high count rate, and ultimately reduced the relative error of the NFM system to less than 2%.