Raman lidar for analysis of industrial atmospheric pollutants

A Raman lidar has been developed for remote analysis of industrial plumes. The fust test results were obtained. The Raman spectrum was excited by the fourth harmonic of a YAG laser. The signals received were recorded by a multichannel system which counts individual photoelectrons. A UMI-93 image converter tube combined with an isocon television camera tube or three FÉU-106 photomultipliers were used as the light detectors. The gases SO₂, CO₂, N₂, O₂, and H₂O were recorded in a plume from a thermal power plant at a distance of 200 m. For a signal-to-noise ratio of 2, probed layer 22.5 m thick, distance of 100 m, and measurement time of approximately 3.5 min (10⁴ laser pulses at a repetition frequency of 50 Hz), the sensitivity was 50 ppm.