Development and Research of a Laser Photo-Acoustic SF6 Gas Analyzer

摘要

An analysis of various optical schemes for the development of a laser SF6 gas analyzer based on a CO2 laser operating in free-running mode and a resonant photo-acoustic detector (PAD) is presented. The use of a sealed gas-filled cell to normalize PAD signals on the absorbed power in the cell is suggested. Compensation for the influence of the tuning of the CO2 laser wavelength near 10.6 mu m on measured SF6 concentration is possible. The results of experimental studies of a laser photo-acoustic SF6 gas analyzer at various concentrations, including in the air flow, are presented. It is shown experimentally that the relative measurement error of the SF6 concentration due to the instability of the laser radiation wavelength does not exceed 5% in the range from similar to 80 ppb to 40 ppm. The limit of the sensitivity of the developed gas analyzer was similar to 1 ppb SF6.