摘要 为了提高激光诱导击穿光谱技术对微量元素定量分析的精度,降低谱线自吸收效应的干扰,实验以攀钢生铁标准样品中的Mn元素作为研究对象,探索激光诱导击穿光谱特征和自吸收效应随着不同离焦量及延时时间参数的变化规律;通过分析不同延时时间和不同离焦量下等离子体光谱强度、等离子体温度、定标曲线决定系数R2和自吸收系数的变化趋势,来寻找最佳延时时间与最佳离焦量。结果显示,定标曲线决定系数R2随着延时时间的增大总体呈下降趋势,随离焦量的增大是先急剧增加再缓慢减小,在离焦量为-2.5mm时达到最大值0.9988;自吸收系数随延时时间的增大逐渐减小,随离焦量的增加是先增大后减小,在-3.75mm时自吸收效应最弱。综合可得,最佳延时时间条件为2μs左右,最佳离焦量在-2.5~-3.75mm范围内。结果表明,通过不断调整和优化系统参数,能够在一定程度上降低自吸收效应,提高定量分析的精度。该实验为探索系统参数对激光诱导击穿光谱特征和自吸收效应的影响提供了一种新的途径和参考依据。 In order to improve the accuracy of trace elements quantitative analysis and reduce the interference of spectral line self-absorption effect for laser-induced breakdown spectroscopy(LIBS),Mn in pig iron CRM from Pangang Group was taken as the research object to explore the characteristics of laser-induced breakdown spectroscopy and the variation law of self-absorption effect with the parameters of different defocusing and delay time.The optimal defocusing and delay time were obtained by analyzing the change trends of plasma spectral intensity,plasma temperature,determination coefficient R2 of calibration curve and self-absorption coefficient under different defocusing and delay time.The results showed that the determination coefficient R2 of the calibration curve generally decreased with the increasing of delay time.While,it increased sharply at first and then decreased slowly with the increasing of defocusing,which reached a maximal value of 0.9988 at defocusing of-2.5mm.The self-absorption coefficient decreased gradually with the increasing of delay time.While,it increased first and then decreased with the increasing of defocusing,which reached a minimal value of-3.75mm.The optimal delay time was about 2μs and the optimal defocusing was within-2.5--3.75mm.The results showed that the self-absorption effect could be reduced and the accuracy of quantitative analysis could be improved in some degree by adjusting and optimizing the system parameters.This experiment provided a new approach and reference basis for exploring the influence of system parameters on the characteristics of laser induced breakdown spectroscopy and the self-absorption effect.
出处 《冶金分析》 CAS 北大核心 2020年第12期51-58,共8页 metallurgical Analysis
基金 国家自然科学基金(No.61705064,No.11647122) 湖北省自然科学基金(No.2018CFB773) 湖北省教育厅团队研究(T201617)。
关键词 激光诱导击穿光谱(LIBS) 自吸收效应 延时时间 离焦量 laser-induced breakdown spectroscopy(LIBS) self-absorption effect delay time defocusing
