Raman Gas Analyzer of Carbon Isotopologues with 50 ppm Level Sensitivity

Nowadays, the concentration of greenhouse gases such as methane (CH 4 ) or carbon dioxide (CO 2 ) in the atmosphere greatly increased. For ecological purposes, it is relevant to discriminate different sources of CH 4 and CO 2 emissions (e.g., antropogenic ones) [1] – [3] . One approach to do this is to monitor the carbon isotope ratio, 13 C/ 12 C, in the greenhouse gases. It can be done, e.g., by Raman gas spectroscopy. In the present work, we describe the results on calibration of a Raman gas analyzer in terms of gas volume fraction measurements, as well as determine the limit of detection (LOD) for two methane isotopologues - 12 CH 4 and 13 CH 4 .