利用甲烷分子在中红外3.31 μm波段的吸收特性，设计并研制了一种便携式甲烷检测仪。为了研究仪器的稳定性，对其在体积分数为0×10-6气体下的输出电压信号做了长时间测试，结果显示，由于环境温度发生变化，半导体电子元件和光学元件参数以及甲烷分子吸收系数均发生漂移，使检测仪输出电压信号的相对漂移达1%。为了抑制温度变化对仪器检测性能的影响，进一步实验研究了仪器输出电压随温度的变化关系，并根据这一关系，对温度漂移造成的信号偏差进行了补偿。引入温度补偿后的实验结果显示，针对体积分数为0×10-6的样品气体，仪器输出电压每周相对波动从1%降至0.46%，体积分数波动范围从86×10-6降至37×10-6。针对体积分数为3250×10-6的样品气体，计算了仪器的阿伦方差曲线，当采样时间大于500 s时，阿伦方差几乎趋于定值，其标准差小于10×10-6。因此，通过温度补偿，在一定程度上消除了环境温度的影响，从而改善了仪器的稳定性。

Using the mid-infrared absorption property of methane molecular at 3.31 μm, a portable methane detector is designed and developed. Long-term measurement on the output voltage is performed under the sample gas with volume fraction of 0×10-6 to study the device′s stability. The results show that, because of environmental temperature change, semiconductor electronic components′ parameters, optical components parameters, and methane molecular absorption coefficients all drift. To suppress the effect of temperature change on detection performances, the relationship between the output sensing voltage and ambient temperature is studied experimentally, and voltage shift caused by temperature drift is compensated. Experimental results after temperature compensation show that, the variation range of output sensing voltage can be reduced weekly from 1% to 0.46% under the sample gas with volume fraction of 0×10-6, and the gas volume fraction value can be dropped from 86×10-6 to 37×10-6. The Allan variance of the detection device is also plotted for the sample gas with volume fraction of 3250×10-6. The Allan variance value almost tends to be a constant when the sampling period is longer than 500 s, and the standard deviation value is less than 10×10-6. Therefore, by virtue of temperature compensation, the effect of environmental temperature change can be well eliminated, and the instrument′s stability can thus be improved.