LIBS; Diffuse reflectance; Portable instrument; Hybrid spectrometer; Pigments;IN-SITU; CULTURAL-HERITAGE; MULTITECHNIQUE APPROACH; WALL PAINTINGS; RAMAN ANALYSIS; LIBS; FIBER; ART; IDENTIFICATION; FLUORESCENCE

A novel, portable spectrometer, combining two analytical techniques, laser-induced breakdown spectroscopy (LIBS) and diffuse reflectance spectroscopy, was developed with the aim to provide an enhanced instrumental and methodological approach with regard to the analysis of pigments in objects of cultural heritage. Technical details about the hybrid spectrometer and its operation are presented and examples are given relevant to the analysis of paint materials. Both LIBS and diffuse reflectance spectra in the visible and part of the near infrared, corresponding to several neat mineral pigment samples, were recorded and the complementary information was used to effectively distinguish different types of pigments even if they had similar colour or elemental composition. The spectrometer was also employed in the analysis of different paints on the surface of an ancient pottery sherd demonstrating the capabilities of the proposed hybrid diagnostic approach. Despite its instrumental simplicity and compact size, the spectrometer is capable of supporting analytical campaigns relevant to archaeological, historical or art historical investigations, particularly when quick data acquisition is required in the context of surveys of large numbers of objects and samples. (C) 2017 Elsevier B.V. All rights reserved.

LIBS; Femtosecond; Organic solar cell; Selective ablation; Depth profiling;DEPTH-RESOLVED ANALYSIS; SELECTIVE ABLATION; SOLAR-CELLS; SPECTROMETRY; LIBS; ABSORPTION; COATINGS; SPECTRA; SAMPLES; PULSES

The potential of laser induced breakdown spectroscopy (LIBS) as a non-contact probe, for characterizing organic photovoltaic devices during selective laserscribing, was investigated. Samples from organic solar cells were studied, which consisted of several layers of materials including a top electrode (Al, Mg or Mo), organic layer, bottom electrode (indium tin oxide), silicon nitride barrier layer and substrate layer situated from the top consecutively. The thickness of individual layers varies from 115 to 250 nm. LIBS measurements were performed by use of a 40 femtosecond Ti:Sapphire laser operated at very low pulse energy (<10 micro-joule) to ensure a fine depth-profiling of the very thin layers. Probing a fixed spot on the sample with successive laser pulses, produced plasma emission spectra corresponding to individual laser ablation events. This enabled discrimination of the different layers on the basis of characteristic spectral lines reflecting key elemental constituents of each layer in the organic solar cell structure, demonstrating the potential of LIBS for fast, non-contact characterization of organic photovoltaic coatings. (C) 2016 The Author(s). Published by Elsevier B.V.

BIVALVE SHELLS; SR/CA; HETEROGENEITY; PALEOCLIMATE; EDULIS; BA/CA; LIBS

Records of past environmental conditions in shell carbonate are usually derived from compositional analysis (i.e. trace elements, stable oxygen, carbon, and nitrogen isotopes) performed along the direction of the shell's growth and thus through time. However, compositional variations within isochronous parts of the shell can distort the environmental record and are difficult to assess without extensively mapping the whole shell. Here we apply Laser Induced BreakdownSpectroscopy (LIBS) to efficiently map the elemental change throughout the growth increments of three mollusc shells (Conomurex fasciatus, Ostrea edulis, Anomalocardia flexuosa). We employ an automated LIBS setup to map the Mg/Ca composition of whole shell sections with over 2000 data points per hour. By assessing the spatial variability of Mg/Ca intensity ratios this method has the potential to mitigate distorted results while increasing the resolution of derived palaeoenvironmental information.

Portable LIBS; Micro-invasive investigation; Pyrotechnological materials; Late bronze age workshop contexts; Tiryns-Greece;PIGMENT ANALYSIS; PAINTED PLASTER; COPPER; ABLATION; IRON; ENVIRONMENT; INSTRUMENT; ARTWORKS; BRONZES; GLASSES

Laser-Induced Breakdown Spectroscopy (LIBS) was used in the investigation of pyrotechnological materials (metal and ceramic items, glass-based objects, plaster-based materials) from several Late Bronze Age workshop and activity area contexts at Tiryns, Greece. The use of a portable instrument, which could be brought into the study place where all objects were housed, was crucial in order to establish the elemental content or verify the material composition of almost all materials analysed. In almost all cases, the LIBS analyses led to the preliminary identification of the materials investigated. In most cases, the results sufficed to confirm earlier research carried out or was in agreement with similar analyses published in the literature. The analyses demonstrate that the micro-invasive LIBS technique provides useful preliminary elemental characterization of most of the pyrotechnological materials while for some, additional work needs to be conducted for securing conclusive results. Essentially, the portability and compactness of the instrumentation enable its use in any workspace with a solid desk, light and electricity access which makes this technique very attractive for obtaining preliminary elementary results. While the technique remains limited by spot analyses it does open up an immense array of possibilities for routine characterization or speedy screening of different types of artefacts in any storage or museum context. These important methodological and scientific findings are considered prerequisite steps leading towards and aiding in responsible sampling strategies for further analyses. (C) 2017 Elsevier Ltd. All rights reserved.

The years 1289-1313 witnessed particularly prolific minting activities at different southern and central Greek mints on behalf of different polities. The coin issues are of great economic and political relevance, and therefore of interest to modern historians. Our understanding of these is based on traditional sources, either numismatic (types and finds), or historical. This paper aims to investigate the possibilities of adding further details to the picture through archaeometry. Specifically, tournois pennies of the three main mints of the region (Clarentza, Thebes, Naupaktos) excavated at Ancient Corinth were analysed according to two different non-destructive methods, X-ray fluorescence spectrometry (XRF) and laser-induced breakdown spectroscopy (LIBS). The resulting relative silver percentages and the fingerprints of the trace elements have supported our attempts to put the different coin types in chronological order and to add detail to the context and intent for each one of these. A vivid picture of monetary production emerges. The different issuing authorities were usually intent on maintaining a decent standard while variously trying to put pressure on rivals or to harmonise their productions with their allies. All the analysed mints were commercial in character, though they were subject to the great political changes affecting Greece in this period, the ambitions of the Angevin dynasty, the various challenges which it faced in Athens, the Peloponnese and the western Mainland, and finally the destructive arrival of the Catalans. In times of need, specifically military, these same mints could therefore rely on further bullion which reached them through internal or external political channels.