为了改善激光诱导击穿光谱稳定性, 提出了一种双谱线内标算法, 采用分析谱线强度与两条内标谱线强度之和归一化的方式提高分析光谱的稳定性。以钢铁中的硅元素谱线Si Ⅰ 288.16nm为例, 对算法进行了数值计算和模拟, 最后以锰和铜谱线为例对算法的普遍性进行了验证。结果表明, 在激光诱导等离子典型温度和电子数密度区域, 采用双谱线内标算法比普通内标法能更有效地改善分析谱线的稳定性。

Dual-line internal standard algorithm was proposed to improve the stability of laser-induced breakdown spectroscopy. The intensity of analysis line was normalized by the sum of the intensity of both the internal standard spectral lines in order to enhance the stability of the spectrum. The line Si Ⅰ 288.16nm of silicon element in steel was used for theoretical calculation and numerical simulation of dual-line internal standard algorithm, finally the universality of the algorithm was validated by taking manganese and copper lines as an example. The results show that, under the typical temperature and electron density in the laser-induced plasma, the dual-line internal standard algorithm can more effectively improve the stability of spectral lines than ordinary internal standard method.