基于FPGA的单光子脉冲信号发生器设计

Design of single-photon pulse generator based on FPGA

针对光电倍增管(Photomultiplier Tube,PMT)批量测试实际需求和单光电子谱精确测试光源的要求,通过对光电倍增管性能测试系统进行分析,设计制造了一种多通道输出可调的脉冲信号发生器的控制板,可用于光电倍增管单光电子谱的性能测试。该脉冲信号发生器在上升时间、下降时间等参数性能方面优于目前测试系统采用的商用信号源RIGOO-DG5352 350 MHz。用此脉冲信号发生器对光电倍增管进行单光电子测试,其输出信号能满足单光子测试的基本要求,利用其多路信号输出的特点,通过性能扩展即可用于光电倍增管的批量测试。

Background： Many performance parameters of photomultiplier tube （PMT） are tested on the basis of the single photoelectron spectroscopy, so single-photon source is essential to the batch test of PMT and requirements of light source for precise single photo electron spectrum measurement. Purpose： The study aims to design a single-photon pulse generator used in batch test for PMT. Methods： A control panel for the adjustable pulse signal generator with multi-channel output is designed and implemented after the performance test analysis of PMT. A MAX10-10M08SAE144C8G FPGA （Field-Programmable Gate Array） chip, a STM32F107 ARM （Acorn RISC Machine） controller and a DP83848 Ethernet chip are integrated to realize desired functionalities. PC sends commands to STM32F107 via Ethernet; then ARM controller analyzes commands and sends them to FPGA to achieve adjustable duty cycle, and adjustable frequency, adjustable amplitude pulse output through the level conversion chip. Results： Compared with the most often used RIGOO-DG5352 signal generator, the newly-designed single-photon pulse generator showed better performance on both the fall time and the rise time. Conclusion： The output signals of this single-photon pulse generator could match the requirements in the PMT single photo-electron spectrum test. Also it can be extended to multi-channel outputs for PMT batch test.