为了研究六氟化硫(SF6)气体分子和水汽(H2O)对一氧化碳(CO)气体分子的弛豫率的影响, 建立了一个基于石英增强光声光谱(QEPAS)技术的痕量气体传感器系统。采用1.57 μm的近红外分布式反馈二极管激光器作为激励光源, 并对不同SF6和H2O气体浓度下的CO的光声信号进行对比研究。首先用CO传感器系统探测CO与N2的气体混合物中CO的光声信号, 然后在CO与N2气体混合物中加入不同浓度的SF6气体, 分别探测不同浓度SF6气体下的CO光声信号强度。最后在CO与N2的气体混合物中加入不同浓度H2O, 探测加入H2O后的CO的光声信号强度。实验结果表明随着CO和N2气体混合物中SF6气体浓度的增加, CO的光声信号幅值几乎没有变化, 而在混合物中加入2.5%的H2O后, 发现CO的光声信号提高了约5倍。因此, SF6对CO气体的弛豫率没有明显的影响, 然而H2O的添加能够有效缩短CO气体的弛豫时间。

A CO sensor system based on quartz-enhanced photoacoustic spectroscopy technology was established to study the effect of sulfur hexafluoride (SF6) and water vapor (H2O) on the relaxation rate of carbon monoxide (CO) gas molecules. A 1.57 μm near-infrared distributed feedback diode laser was used as the light source to compare the photoacoustic signal amplitudes of CO under different concentrations of SF6 and H2O. First, a CO sensor system was used to detect photoacoustic signals from CO in a gas mixture of CO and N2. Then, different concentrations of SF6 gas were added to the CO and N2 gas mixture and the photoacoustic signal amplitudes of CO were detected. Finally, H2O was added to the gas mixture of CO and N2 before detecting the photoacoustic signal amplitudes of CO. The experimental results show that with increasing concentration of SF6 in the gas mixture of CO and SF6, the photoacoustic signal of CO remains constant; however, the addition of 2.5% H2O to the mixture results in a five-fold increase of the photoacoustic signal of CO. Therefore, H2O has an obvious effect on the relaxation rate of CO gas, while SF6 has none.