Investigation On The Trace Gas Concentration Of Carbon Monoxide Based On Cavity Ring-down Spectroscopy

Greenhouse gases are one of the key factors affecting and changing the global climate,so restricting and reducing greenhouse gas emissions has become an important issue for human development.The greenhouse gases have low content in the atmosphere and large differences in molecular structure.It is difficult to obtain high measurement accuracy by traditional methods.In recent years,cavity ring-down spectroscopy has become a new method to measure trace elements with high sensitivity and accuracy.For the analysis of the molecular spectrum of trace gases,pCqSDNGP line can well characterize the absorption line,which is the most perfect linear,and the fitting residual is closest to the noise level of the device.In this paper,based on the frequency stabilization of cavity ring-down spectroscopy is traced back to the gas concentration molecular spectral line,we measured the nominal concentration of 200 ppm,20 ppm of carbon monoxide R12(3?0)and R17(3?0),R18(3?0)molecular absorption spectrum,and at the same time,researched on six commonly used linear,including pressure related narrow bandwidth,collision effect,as well as the speed change collision and associated phase depend on the effects of the relaxation rate,etc.Using pCqSDNGP(Partially Correlated quadratic Speed-Dependent Nelkin-Ghatak profile)linear fitting of measured spectra obtained spectral parameters and absorption peak area,it is concluded that the absorption spectra under different pressure area's relationship with mass concentration.The experiment measuring density and scale standard of weighing method,both have good consistency.Both concentration difference is less than 0.5%,the whole experiment process of uncertain set at 0.41%,has realized the spectrum method and based on the concentration of the weighing scales benchmark equivalent,also proved that the feasibility of using optical cavity ring down spectroscopy to realize the greenhouse gas base.cavity ring down spectroscopy is the ideal of a new generation of greenhouse gas measurement standards.