An Investigation of Enhanced Laser-Induced Spark Emission and Material Ablation Following Sequential Laser PulseExcitation

南卡罗来纳大学的 Stanley Angel 教授得到了与意大利巴里大学的 A. DeGiacomo 博士合作的分析和表面化学项目的支持。 通过实验和理论，该团队正在研究原子分析方法激光诱导击穿光谱（LIBS）的机理，以改进 LIBS 作为无需样品制备即可分析固体的技术。 特别是，双脉冲序列导致 LIBS 增强 100 倍，但增强的机制、更大的等离子体体积、更低的连续背景和增加的电子温度尚不清楚。 将进行系统研究来检验以下假设：这些影响是由于样品上方的等离子体重新加热和预电离造成的。 例如，该团队将尝试通过使用辉光放电创建预电离区域来复制双脉冲结果。 三种样品基质（玻璃、钢和纯金属）中的四种元素：铝、铁、铜和铬将作为模型系统进行研究。应用包括环境、健康、法医、地质和工业分析。这项工作将使学生能够与国际科学家以及劳伦斯利弗莫尔国家实验室的工作人员互动。

Professor Stanley Angel of the University of South Carolina is supported by the Analytical and Surface Chemistry program in a collaboration with Dr. A. DeGiacomo of the University of Bari, Italy. Through experiments and theory, the team is studying the mechanism of an atomic analytical method, laser-induced breakdown spectroscopy (LIBS), in order to improve LIBS as a technique capable of analyzing solids without sample preparation. Particularly, a dual pulse sequence has resulted in 100-fold enhanced LIBS, but the mechanism for the enhancement, larger plasma volume, lower continuum background and increased electron temperature are not known. Systematic studies will be conducted to test the hypothesis that the effects are due to plasma re-heating and pre-ionization above the sample. For example, the team will attempt to duplicate dual-pulse results by creating a pre-ionized region using glow discharge. Four elements, Al, Fe, Cu and Cr, in three sample matrices (glass, steel and pure metals) will be studied as model systems.Applications include environmental, health, forensic, geological and industrial analysis. The work will enable students to interact with international scientists as well as staff at the Lawrence Livermore National Laboratory.