Multi-Pulse Excitation for Underwater Analysis of Copper-Based Alloys Using a Novel Remote Laser-Induced Breakdown Spectroscopy (LIBS) System

Abstract

In this work, the use of multi-pulse excitation has been evaluated as an effective solution to mitigate the preferential ablation of the most volatile elements, namely Sn, Pb, and Zn, observed during laser-induced breakdown spectroscopy (LIBS) analysis of copper-based alloys. The novel remote LIBS prototype used in this experiments featured both single-pulse (SP-LIBS) and multi-pulse excitation (MP-LIBS). The remote instrument is capable of performing chemical analysis of submersed materials up to a depth of 50 m. Laser-induced breakdown spectroscopy analysis was performed at air pressure settings simulating the conditions during a real subsea analysis. A set of five certified bronze standards with variable concentration of Cu, As, Sn, Pb, and Zn were used. In SP-LIBS, signal emission is strongly sensitive to ambient pressure. In this case, fractionation effect was observed. Multi-pulse excitation circumvents the effect of pressure over the quantitative analysis, thus avoiding the fractionation phenomena observed in single pulse LIBS. The use of copper as internal standard minimizes matrix effects and discrepancies due to variation in ablated mass.

Identifying Ancient Ceramics Using Laser-Induced Breakdown Spectroscopy Combined with a Back Propagation Neural Network

“…LIBS has been widely used in environmental, 9 biological, 10–12 industrial, 13 and archeological fields 14–18 and in other domains. 19–23 In addition, transporting archeological samples to specialized analytical laboratories is typically subject to strict regulations and entails lengthy procedures. Meanwhile, LIBS technology is a micro-destructive and fast component analysis technique.…”

A Review of Underwater Laser-induced Breakdown Spectroscopy of Submerged Solids

“…129 On the other hand, Guirado et al have reported that the fractionation effect in the laser ablation of Cu-Zn alloy was mitigated by the use of multi-pulses instead of single-pulse for the underwater LIBS measurement. 136…”

Fast and In-Situ Identification of Archaeometallurgical Collections in the Museum of Malaga Using Laser-Induced Breakdown Spectroscopy and a New Mathematical Algorithm

“…This approach has been employed in the elemental analysis of artworks located in museum, caves, historical building, or monuments [22,23]. Regarding the importance of the corrected preservation and protection of submerged cultural heritage, in-situ and stand-off LIBS technology for subsea analysis of archaeological and shipwreck objects has been also reported [24][25][26][27]. The performances of underwater analysis have been improved by using multi-pulse LIBS excitation [25].…”

“…Regarding the importance of the corrected preservation and protection of submerged cultural heritage, in-situ and stand-off LIBS technology for subsea analysis of archaeological and shipwreck objects has been also reported [24][25][26][27]. The performances of underwater analysis have been improved by using multi-pulse LIBS excitation [25]. The remote LIBS arrangement proposed by Fortes et al was capable of inspecting a copper-based alloy located at depths of up 30 m under the Mediterranean Sea [26].…”