Carbon monoxide ,as a kind of dangerous mine gas ,can easily accumulate in a complex mine environment poses a seri-ous threat to the safety of miners .This paper presents a compact carbon monoxide detector .This instrument have a mid-infrared quantum cascade laser operating at 4.65μm as light source ,with mercury cadmium telluride (HgCdTe) detector and 12 m com-pact absorption path to obtain trace-CO diagnostics .Self-designed high-speed photoelectric signal acquisition system solved the signal chain impedance mismatch problem which caused by commercial oscilloscope .This new acquisition system realized 1GSPS sampling rate and vertical resolution of 12 bit at 400 M Hz sampling bandwidth which improved the detector''s sensitivity and in-tegration effectively .This instrument use long path differential optical absorption spectroscopy (LP-DOAS) theory .The detec-tion limit of the instrument which gives as 108 × 10-9 is obtained by comparing the residual between the measured spectrum and calculated theoretical spectrum with Voigt broadening .Detector''s measurement error has non-stationary ,slowly time-varying characteristics .According to this feature we use Allan deviation to estimated detector ''s sensitivity ,after about 40 seconds the deviation curve reached the minimum .The Allan deviation value is 61× 10-9 .In two-hour tests ,the stability of the detector is 2.1× 10-3 ,for up to 12 hours of stability tests ,the detector''s stability can still reach 1.7 × 10-2 .This instrument has high flexibility ,through the replacement of different laser with different lasing wavelength;it can be achieved on a variety of trace gas detection .%一氧化碳作为一种危险的开采排放气体,在复杂的井下环境中极易累积,对矿工生命安全造成严重威胁.介绍了一种紧凑型一氧化碳检测仪,该仪器采用激发波长为4.65 μm的量子级联激光器作为光源,配合中红外碲镉汞光电探测器与光程长度12 m的紧凑型多次反射气室,实现了对痕量一氧化碳气体的检测.自主设计的新型高速光电信号采集系统解决了应用商业示波器造成的信号链阻抗失配的问题.这一新系统的采样带宽为400 MHz,采样频率1GSPS,垂直分辨率达到12 bit,有效的提高了检测仪的灵敏度与集成度.该仪器采用长光程差分吸收光谱法,通过比较实测光谱与进行Voigt展宽的理论光谱之间的残差得出此检测仪的检测下限为108×10-9.检测仪的测量误差有非平稳,慢时变的特点.根据这一特点我们采用阿伦方差对气体检测仪检测灵敏度进行了估计,经过约40 s方差曲线达到极小值,此时阿伦方差值为61×10-9.在2 h的稳定性测试中,检测仪稳定度达到2.1×10-3,在长达12 h的稳定性测试中,检测仪的稳定度依然可以达到1.7×10-2.此仪器具有较高的灵活性,通过更换不同激射波长的激光器可以实现对多种气体的痕量检测.
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