CO<inf>2</inf>-laser photoacoustic detection of heavy water vapour. Basic principles

Abstract

A CO2-laser cw system and a photoacoustic detection apparatus, based on a nonresonant gas cell, was constructed and built. Coincidences of D2O absorption with several laser lines were observed. The strongest absorption was observed with the line at 9.26 μm, which was used in the experiments. Samples of deuterated water in the range from 10 to 100% deuterium were used to examine the behaviour of the photoacoustic signal under conditions of varying deuterium content and total vapour pressure. A principal calibration procedure with respect to this is proposed. The behaviour of the system on buffer gas introduction was examined with hydrogen and dry air. Self-buffering of water vapour is also discussed on the basis of the results. © 1989 Akadémiai Kiadó.