Method for measuring the concentration of a gas component in a measuring gas

摘要

The invention relates to a method for measuring the concentration of a gas component (8) in a measuring gas (7), wherein the light (2) of a wavelength tunable light source (1) is passed along a single optical path through a measuring volume (3) containing the measuring gas (7) and a reference cell (4) containing a reference gas (9) to a detector (5). According to the invention the reference cell (4) is selected to contain a selected isotope of the gas component (8) to be measured in a known abundance ratio higher than the known natural-abundance isotope ratio of the gas component (8) in the measuring volume (3); the light source (1) is tuned to sweep the wavelength of the light (2) over the absorption lines of the selected isotope and the remaining gas component; and the concentration of the gas component (8) in the measuring volume (3) is calculated from the ratio of the detector signals (6) at the peaks of the absorption lines, based on Lambert's law and taking into account the known abundance isotope ratios.