Cao Yuan, Wang Ruifeng, Peng Jie, Liu Kun, Chen Weidong, Wang Guishi, Gao Xiaoming
Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China.
University of Science and Technology of China, Hefei, 230026, China.
Photoacoustics. 2021 Sep 10;24:100303. doi: 10.1016/j.pacs.2021.100303. eCollection 2021 Dec.
A high-sensitivity NO photoacoustic sensor using a 4.53 μm quantum cascade laser was developed. Sharply enhancement of photoacoustic signal of NO with the increasing of humidity was investigated experimentally. Finally, 2.3 % water vapor was added to the analyzed sample to improve the vibrational-translational (V-T) relaxation rate of NO molecule transition, and therefore enhance the NO photoacoustic signal. High performance with a minimum detection limit of 28 ppbv in 1 s and a measurement precision of 34 ppbv have been achieved, respectively. Kalman adaptive filtering was used to remove the shot-to-shot variability related to the real-time noise in the measurement data and further improve the measurement precision. Without sacrificing the time resolution of the system, the Kalman adaptive filtering improves the measurement precision of the system by 2.3 times. The ability of the NO photoacoustic sensor was demonstrated by continuous measurement of atmospheric NO concentration for a period of 7 h.
开发了一种使用4.53μm量子级联激光器的高灵敏度一氧化氮光声传感器。通过实验研究了随着湿度增加一氧化氮光声信号的急剧增强。最后，向分析样品中添加2.3%的水蒸气，以提高一氧化氮分子跃迁的振动-平动（V-T）弛豫速率，从而增强一氧化氮光声信号。分别实现了1秒内28 ppbv的最低检测限和34 ppbv的测量精度的高性能。使用卡尔曼自适应滤波来消除与测量数据中的实时噪声相关的逐次变化，并进一步提高测量精度。在不牺牲系统时间分辨率的情况下，卡尔曼自适应滤波将系统的测量精度提高了2.3倍。通过连续7小时测量大气中的一氧化氮浓度，证明了一氧化氮光声传感器的能力。
