SF

6

is a kind of excellent insulating gas and is normally used inside GIS. It

in case of abnormal operation of GIS

may decompose

generating a variety of decomposed components and one of which is CO

therefore

the quantitative measurement of CO is of great significance. In this paper

the CO near infrared absorption band with center band of 6 377.406 6 cm

-1

is selected as the study object on the basis of photo acoustic effect of the gas and the measurement of Michelson interferometer on the deformation of the can

tilever beam. The DFBLD near infrared butterfly laser with center wavelength of 1 567 nm is used to set up trace CO gas detection platform. The influence of internal temperature and intensity of pressure in the gas pool on CO infrared absorption coefficient and amplitude of static photo acoustic signal is analyzed. The relationship between the amplitude of the net photo acoustic signal and CO gas volume fraction at the background of SF

6

and N

2

is quantitatively measured and analyzed. The result shows that there is a good linear relation between the CO gas volume fraction and the amplitude of the net photo acoustic signal. The lower limit of CO detection at the background of N

2

is up to 3.63 μL/L and that at the background of SF

6

is up to 9.88 μL/L. The temperature and intensity of pressure have a definite influence on the amplitude of photo acoustic signal. The photo acoustic signal decreases and increases respectively with the rise of temperature and the increase of intensity of pressure.