大气颗粒物中重金属的双脉冲激光诱导击穿光谱研究

为了对沈阳市某工业区附近大气中重金属等离子体光谱特性进行研究，采用双脉冲激光诱导击穿光谱技术（Double pulse laser induced breakdown spectroscopy，DP-LIBS）对样品中主要重金属等离子体光谱进行测量分析。通过比较单脉冲（SP）和双脉冲（DP）激发的样品等离子体光谱，发现采用DP-LIBS技术可以很好地增强等离子体光谱的强度。研究DP-LIBS光谱强度随两个脉冲激光的间隔时间变化，在脉冲间隔为15 s时样品中重金属等离子体光谱得到了最大的增强。同时DP-LIBS技术也会提高样品等离子体光谱的稳定性，谱线的相对标准偏差由6%降低为3%左右。最后对样品等离子体的电子温度及电子密度随双脉冲间隔时间的变化情况进行了研究。

Analysis of the heavy metals in atmospheric particulate matter using dual-pulsed laser-induced breakdown spectroscopy

In order to study the spectral characteristics of heavy metal plasma in the atmosphere near an industrial zone in Shenyang, double pulse laser-induced breakdown spectroscopy (DP-LIBS) was used to measure and analyze the characteristics of main heavy metal laser-induced breakdown spectra in the atmosphere. By comparing the plasma spectrum of samples excited by single pulse (SP) and double pulse (DP). It was found that DP-LIBS can enhance the intensity of plasma spectrum. The DP-LIBS spectral intensity with the interval time of two pulsed lasers was studied, and the maximum enhancement of the heavy metal plasma spectrum was obtained when the pulse interval was 15 s. At the same time, the DP-LIBSs technology will also improve the stability of the sample plasma spectrum, and the relative standard deviation of the spectrum line will be reduced from 6% to about 3%. Finally, the changes of electron temperature and electron density with the time interval of double pulse were studied.