Development of Carbon Dioxide Detection Device Based on Mid-Infrared Cavity Decay Spectroscopy Technology

With the rapid development of the nuclear industry，the amount of waste to be treated and monitored increases，and the potential emissions will also increase，and C-14 needs to be monitored. C-14 produced by nuclear facilities is mainly combined with CO2，so sensitive monitoring of 14CO2 gas is of great significance. In this paper，cavity ring-down spectroscopy (CRDS) is used to detect the CO2 absorption spectrum by selecting the center wave number of 14CO2 absorption line around 2209.11 cm−1. A CO2 detection system based on mid-infrared cavity ring-down spectroscopy is developed by using a quantum cascade laser in mid-infrared band，an optical resonator，and a reasonable optical path design and gas pipeline design. Based on the developed system，different concentrations of CO2 (0.5%-1.3%) were detected，and the experimental data were fitted and analyzed，and the results were found to be consistent with the theoretical formula，which confirmed the feasibility of the developed mid-infrared cavity ring-down spectrum system. The system has successfully realized the accurate measurement of different concentrations of CO2 gas in the mid-infrared band，the absorption spectrum of 14CO2 was measured by mid-infrared cavity ring-down technique， which provides an important technical support and foundation for the future study of laser spectral detection of 14CO2.