高灵敏度小型化红外光声气体传感系统

摘要

研制了一种高灵敏度小型化红外光声气体传感系统.该系统检测灵敏度高,对乙烯气体体积分数的检测限达到20×10-9以下.对光声信号和检测相位之间的关系进行了详细的研究,分析了光声信号中峰值相位变化的因素.结果表明:在固定相位延迟下利用锁相放大器检测光声信号可以获得比较高的灵敏度.同时根据对光声信号和相位延迟关系的研究,提出了小型化光声腔设计思路.%A prototype of a highly sensitive miniaturized infrared photo-acoustic (PA)system is developed. The system can detect the volume fraction of ethylene gas below 20×10-9. Relationship between the PA signals and the testing phase is focused on, the reason of the phase change in testing is analyzed. A conclusion is obtained that under a fixed phase delay using lock-in amplifier to detect PA signals can get a high sensitivity. According to the research on the PA signal and phase delay. A design of miniature on PA cell is proposed.