基于可调谐CO2激光器的SF6差分光声检测研究

为了对电力场所SF₆气体浓度进行有效监测，采用光声光谱气体检测技术，基于波长可调谐CO₂激光器，设计了一套大气环境下的SF₆痕量气体检测系统，并提出一种差分光声光谱技术以提升光声系统的检测灵敏度。结果表明，所设计的SF₆气体检测光声系统的共振中心频率为1066Hz，品质因数为32.04，光声池常数为89.74Pa·m·W-1；利用单谱线光声法，在激光谱线10P12处检测SF₆气体的灵敏度为0.06×10-6（体积分数）；采用差分光声光谱气体技术后，在激光谱线10P12和10P16处3W强度调制光的照射下，光声系统的灵敏度提升到0.02×10-6（体积分数）。差分光声光谱技术能有效降低噪声影响，提升光声检测系统的灵敏度，具有一定的实用价值。

Research of SF6 detection by means of differential photoacoustic spectroscopy with tunable CO2 laser

In order to monitor SF₆ gas concentration in electric power site effectively, based on wavelength tunable CO₂ laser, a set of SF₆ trace gas detection system under atmospheric environment was designed by means of photoacoustic spectroscopy gas detection technology. Differential photoacoustic spectroscopy technique was proposed to improve detection sensitivity of photoacoustic system. The results show that resonant center frequency of the designed SF₆ gas detection photoacoustic system is 1066Hz, quality factor is 32.04 and photoacoustic pool constant is 89.74 Pa·m·W-1. Sensitivity of SF₆ gas detection at laser spectral line 10P12 is 0.06×10-6(volume fraction) by using single spectrum photoacoustic method. Sensitivity of photoacoustic system at 10P12 and 10P16 and at 3W modulated light increases to 0.02×10-6(volume fraction) after using differential photoacoustic spectroscopy gas technology. Differential photoacoustic spectroscopy can effectively reduce noise effect and enhance the sensitivity of photoacoustic detection system. It has practical value.