SO2 and SF6 collisional relaxation time measurement by laser photoacoustic spectroscopy method

In this experimental study the collisional relaxation time of SO2 and SF6 was determined using laser pho-toacoustic spectroscopy method. A homemade LPAS cell was fabricated in order to investigate the variation of signal and resonant frequency in terms of buffer gas pressure for several species such as: He، N2، and Ar. By this method collisional relaxation (which is the origin of photoacoustic effect) time was measured. It was shown that the buffer gas pressure notably affects the collisional relaxation times of gases such as SO2 and SF6. The measured relaxation times of SO2 and SF6 were at order of milliseconds and 100 microseconds respectively.