Analysis of Self-absorption Effect of Lithium Plasma Plume Produced by Laser Induced Breakdown SpectroscopyAnalysis of Self-absorption Effect of Lithium Plasma Plume Produced by Laser Induced Breakdown Spectroscopy

Laser induced breakdown spectroscopy (LiBS) is known as a fast qualitative and quantitative atomic analysis technology. Self-absorption, in which the center part of the plasma radiation is re-absorbed by the outside cooler plasma region, frequently occurs and affects the LiBS spectra so that researchers focus on correction and suppression of the self-absorption effect. On the contrary, taking the advantages of the narrow line width of the self-absorption, laser-induced breakdown self-reversal isotopic spectrometry was reported for isotopic analysis of lithium. In our work, A LiBS system was constructed to produce Li plasma. A Nd:YAG with the wavelength of 1064 nm was used as the excitation/ionization source and the LiBS signals were analyzed by a high resolution spectrometer. Self-absorption was well detected in the Li spectrum at 670.8 nm. Images of Li plasma plume were also photographed by an iCCD camera and the plasma plume was detected as the elliptical shape. The center of the plasma plume showed more intense than the edge of the plasma plume corresponding to the hot plasma region and the cooler plasma region. Self-absorption phenomenon was discussed by the measured LiBS results combined with the analyzed plasma plume. Conditions to observed Li self-absorption phenomenon in LiBS measurement were optimized.