Micro-Laser-Induced Breakdown Spectroscopy (Micro-LIBS) Study on Ancient Roman Mortars. Issue 4 (April 2017)

• Record Type: Journal Article
• Authors: Pagnotta, Stefano; Lezzerini, Marco; Ripoll-Seguer, Laura; Hidalgo, Montserrat; Grifoni, Emanuela; Legnaioli, Stefano; Lorenzetti, Giulia; Poggialini, Francesco; Palleschi, Vincenzo
• Is Part Of: Applied spectroscopy. Volume 71:Issue 4(2017)
• Page Start: 721
• Page End: 727
• Publication Date: 2017-04
• Subjects: Laser-induced breakdown spectroscopy -- LIBS -- mortars -- binder -- aggregate -- blind separation techniques -- artificial neural networks -- self-organizing maps; Spectrum analysis -- Periodicals; 543.505
• DOI: 10.1177/0003702817695289
• Languages: English
• ISSNs: 0003-7028

Abstract

The laser-induced breakdown spectroscopy (LIBS) technique was used for analyzing the composition of an ancient Roman mortar (5th century A.D.), exploiting an experimental setup which allows the determination of the compositions of binder and aggregate in few minutes, without the need for sample treatment. Four thousand LIBS spectra were acquired from an area of 10 mm 2, with a 50 µm lateral resolution. The elements of interest in the mortar sample (H, C, O, Na, Mg, Al, Si, K, Ca, Ti, Mn, Fe) were detected and mapped. The collected data graphically shown as compositional images were interpreted using different statistical approaches for the determination of the chemical composition of the binder and aggregate fraction. The methods of false color imaging, blind separation, and self-organizing maps were applied and their results are discussed in this paper. In particular, the method based on the use of self-organizing maps gives well interpretable results in very short times, without any reduction in the dimensionality of the system.