Effect of pulse delay time on a pre-ablation dual-pulse LIBS plasma

In this paper, we investigate the effect of dual-pulse timing on material a blation, plasma temperature, and plasma size for pre-ablation spark dual-pu lse laser-induced breakdown spectroscopy (LIBS). Although the plasma temper ature increases for dual-pulse excitation, the signal enhancement is most e asily attributed to increased sample ablation. Plasma images show that the magnitude of the enhancement can be affected by the collection optic and by the collection geometry. Enhancements calculated using the total integrate d intensity of the plasma are comparable to those measured using fiber-opti c collection.