基于TDLAS平衡差分技术的CO气体检测

发布时间：2018-02-09 17:33

  本文关键词： 可调谐半导体激光吸收光谱 平衡差分技术 CO检测　出处：《光谱学与光谱分析》2017年10期 　论文类型：期刊论文

【摘要】：利用可调谐半导体激光吸收光谱(TDLAS)结合平衡差分探测技术测量了1.578μm附近的CO气体3-0带P(4)跃迁在不同压强和不同浓度下的吸收光谱信号。由于平衡差分探测方法可以有效地抑制激光光强波动、温度漂移和机械振动等共模噪声,从而提高了光谱探测灵敏度。通过与直接吸收信号相比,平衡差分的信噪比提高了3.4倍,探测极限为87ppmv。测量了浓度为1%压强为40,55,70和85Torr时的CO气体,结果显示在70Torr时其光谱信号最强。并且,利用直接吸收和平衡差分技术测量了不同浓度的CO气体在总压强在70Torr时的光谱信号,发现平衡差分技术光谱强度与浓度的关系线性度符合较好,其测量误差小于5%。为了进一步验证系统的稳定性,连续采集了324s的光谱信号,最后通过Allan方差分析,发现本实验系统的最佳探测时间为38s,探测极限为47.8ppmv。
[Abstract]:The absorption spectra of CO gas in the vicinity of 1.578 渭 m in 3-0 band Pn4) have been measured by TDLAS-TDLAS-TDLAS-balanced differential detection technique. The absorption spectra of the transition at different pressures and concentrations have been measured. The balanced differential detection method can be used to detect the absorption spectra. In order to effectively suppress the fluctuation of laser light intensity, The common mode noise such as temperature drift and mechanical vibration improves the sensitivity of spectral detection. Compared with the direct absorption signal, the signal-to-noise ratio of the balanced differential signal is 3.4 times higher than that of the direct absorption signal. The detection limit is 87ppmv. the CO gas at the concentration of 1% pressure of 40,550.70 and 85Torr has been measured. The results show that the spectral signal is the strongest at 70Torr. The spectral signals of CO gas with different concentrations at 70 Torr were measured by direct absorption and equilibrium differential technique. It was found that the linear relationship between the spectral intensity and the concentration of CO was in good agreement with the equilibrium differential technique. The measurement error is less than 5. In order to further verify the stability of the system, the spectral signals of 324 s are collected continuously. Finally, by Allan variance analysis, it is found that the optimal detection time and detection limit of the system are 38 s and 47.8 ppmv.
【作者单位】： 太原科技大学应用科学学院;中北大学电子检测技术重点实验室;
【基金】：国家自然科学基金项目(11504256,U1610117,61573323) 中国科学院时间频率基准重点实验室开放基金项目 精密光谱科学与技术国家重点实验室开放课题 山西省高等学校科技创新项目(2014146) 晋城市科技攻关项目(201501004-22)资助
【分类号】：O657.3
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本文编号：1498482