Orthogonal fs/ns double-pulse libs for copper-based-alloy analysis

Abstract

The analytical response of a fs/ns double-pulse laser induced breakdown spectroscopy technique based on the orthogonal reheating induced by a ns-laser pulse on a fs-laser ablation plume is presented. All investigations have been performed in air at atmospheric pressure and employing certified copper-based-alloy targets. The emission intensities of the considered electronic transitions of Pb(I), Sn(I) and Zn(I) have been normalised with a Cu(I) emission line intensity belonging to the same considered spectral range. Emission data, acquired with inter-pulse steps of 2 μs within the delay range of 1–200 μs, have shown that fractionation takes place. Nevertheless, excellent linear regression coefficients (0.998–0.999), despite the target’s large compositional variation and fractionation effects, have been obtained by integrating all emission intensity data along the whole inter-pulse delays used. Deviations from the theoretical ratio of the Zn(I)/Cu(I) emission intensities are shown and some hypotheses about the processes involved are formulated.