基于FPGA的高精度光子计数检测系统研究

摘要

In order to measure weak optical signal, a photon-counting detecting system based on FPGA is designed and constructed. A high sensitivity photomultiplier tube (PMT) is used to obtain the optical signal. The system consists of time scheduling control module, photon-counting module, serial communication module, memory module and key-scanning control module. Adenosine triphosphate(ATP) samples with concentration of 2.5 × 10-14～2.5 × 1O-8 mol/L are measured and the correlation coefficient between ATP concentration and light intensity is 0.9832. Alkaline phosphatase (ALP) samples with concentration of 2.5 × 10 -1～ 5 × 10 ~ mol/L is measured and the correlation coefficient between ALP concentration and light intensity is 0.9982. The system has the characteristics of small size,high precision, and is easy to operate. It can be widely used in detection of low concentrations of substances.%为了实现微弱光信号的高精度检测,设计了一种基于现场可编程门阵列(FPGA)的光子计数检测系统.采用高灵敏度的光电倍增管作为光电转换器件,有效地实现微弱光信号的获取与处理.基于FP-GA,设计了时序控制模块、光子计数模块、串口通信模块、存储模块和键盘扫描控制模块,完成信号的处理与存储.使用该系统对三磷酸腺苷(ATP)样品进行生物发光测试,在ATP浓度为2.5×10-14-2.5×10-8mol/L范围内,系统检测光强与ATP浓度之间线性关系良好,相关系数R=0.983 2;对碱性磷酸酶(ALP)化学发光体系进行测试,在ALP浓度为2.5×10-12-5×10-9mol/L范围内,系统检测光强与ALP浓度之间线性关系良好,相关系数R=0.9982.该检测系统小型便携,检测精度高,在低浓度生物活性物质检测领域具有广阔的应用前景.