Study on Ablation Behaviors and Ablation Rates of a 193nm ArF Excimer Laser System for Selected Substrates in LA-ICP-MS Analysis

Understanding laser ablation behaviors of different target materials is essential for optimum laser parameters, external reference materials selection, as well as for data quality assurance. In this study, ablation behaviors of a 193nm ArF excimer laser for silicate glasses, common minerals, and powder pellets were investigated. Ablation rates influenced by laser parameters (including spot size, energy density, and laser frequency) were evaluated. Topographic images of craters generated during ablation illustrate that glasses and most minerals have controllable ablation behaviors, except for quartz. The worse ablation behavior of quartz may be ascribed to the micro-fluid inclusions, which could result in the overheating effect in laser pits. In general, powder pellets have worse ablation behaviors, but the increase of tableting pressure or reducing the particle grain size could improve the ablation behaviors. Ablation rates gradually decrease if the ablation depth is larger than 1.5 times of the spot size. The maximum ablation depth can reach twice the spot size when the energy density is 3.0 J/cm² for the RESOlution M-50 laser system). Ablation rates increase with the increase of laser energy density, but ablation rates are not affected by the laser frequency (2-20 Hz). Ablation rates are specific to the individual substrates. In conclusion, the ablation rate data of 43 substrates, in which ablation rates of powder pellets are larger than glasses and minerals, whereas those of carbonates and sulfides are larger than silicate minerals, and those of NIST glasses are larger than geological glasses.