Laser cavity ring-down spectrometer for simultaneous detection of aerosol extinction and scattering coefficients

Abstract

The invention relates to a laser cavity ring-down spectrometer for simultaneous detection of aerosol extinction and scattering coefficients. The spectrometer comprises a gas path system, a light cavity, a first photomultiplier and a second photomultiplier, wherein the first photomultiplier is used for detecting transmission light of the light cavity; the second photomultiplier is used for integral measurement of scattered light and stretches into the light cavity from the side surface of the light cavity; the gas path system is used for providing sample gas or background gas for the light cavity periodically. Because the gas path system feeds the background gas and the sample gas with aerosol into the light cavity periodically, the spectrometer disclosed by the invention can detect the transmission light and the scattered light of the light cavity respectively through the first photomultiplier and the second photomultiplier, and can calculate ring-down time of the background gas and ring-down time of the sample gas through fitting respectively, thus calculating extinction coefficient of the aerosol; simultaneously, the spectrometer can calculate ratio of transmission light intensity to scattered light intensity to obtain scattering coefficient of the aerosol, and the spectrometer is low in detection error and high in precision. The ring-down spectrometer disclosed by the invention is applicable to online analysis and detection of optical properties of atmosphere aerosol.

Description

technical field [0001] The invention relates to the field of on-line detection of atmospheric aerosol optical properties, in particular to a laser optical cavity ring-down spectrometer for simultaneously detecting aerosol extinction and scattering coefficients. Background technique [0002] Atmospheric aerosol is an important driving factor of global and regional climate change, but at the same time, aerosol is also one of the biggest sources of uncertainty in current climate research. In addition, the limitation of measurement technology is also an important reason for the great uncertainty in the measurement of aerosol absorption characteristics. Research on new technologies that can simultaneously measure extinction coefficient and scattering coefficient or simultaneously measure scattering coefficient and absorption coefficient has important practical value and significance for atmospheric science research and meteorological fields. [0003] Optical cavity ring-down spe...

AI Technical Summary

Problems solved by technology

However, this method, which uses two different instruments to measure the extinction coefficient and the scattering coefficient separately, will be affected by the uncertainty of the synchronization of the sample analysis time; more importantly, the working wavelength of the extinction coefficient measurement is usually the same as the working wavelength of the scattering coefficient measurement. Inconsistency requires additional calculations. Unifying the two to the same wavelength will introduce calculation method errors and increase the uncertainty of single-scattering albedo measurements.

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