Long Path Differential Optical Absorption Spectroscopy Based on CCD
以CCD为探测器的长程差分吸收光谱系统

The long path differential optical absorption spectroscopy (LP-DOAS) technique was presented.A charge coupled device (CCD) was employed as the detector.The properties of the system were described,including offset,dark current,noise,linearity of the detector and spectral resolution,wavelength range,stray light of the spectrometer.Field observations for SO2,NO2 and HONO were performed in Beijing,and time series of SO2,NO2 and HONO concentration were listed,and the detection limits of this system for SO2,NO2 and HONO over a 920 meter light path were determined.A comparison between the DOAS system and traditional point monitoring techniques for the results of SO2,NO2 showed that quite good correlation could be established,so the system is suitable for monitoring many trace gases.The results of field observations show that this system is more predominant and it allows long-term measurements of many trace gases.