Cultural heritage; Laser scanners; Fiber Bragg grating sensor; Laser-induced fluorescence; Laser-induced breakdown spectroscopy;INDUCED BREAKDOWN SPECTROSCOPY; PLASMA PARAMETERS; FLUORESCENCE

The recent development of laser scanners in environmental diagnostics made possible to implement their prototypes for remote characterization of cultural heritage (CH) surfaces. Specific data analysis algorithms have been developed to handle large data set acquired in high resolution operation. Non-invasive, or at least micro-invasive methodologies applied on real CH targets have shown the possibility to obtain information on surface appearance, morphology and composition. The added value of optical and spectroscopic integrated sensors is discussed for some significant case studies addressed both to a deep knowledge of the artifacts (materials and methods of realization) and to their structural characterization.

LIBS; Hydrogen isotopes; Plasma-facing-components; ITER; Laser diagnostics; Fusion reactors;EMISSION; PLASMA; ENHANCEMENT; TUNGSTEN; SAMPLES; LIBS; ABLATION; SPECTRA; TRITIUM; SPARK

The amount of hydrogen isotopes retained in plasma facing components (PFCs) and the determination of their surface layer composition are among the most critical issues for the next generation fusion device, ITER, under construction in Cadarache (France). Laser Induced Breakdown Spectroscopy (LIBS) is currently under evaluation as a technique suitable for quantitative, in situ, non-invasive measurements of these quantities. In order to detect traces of contaminant in metallic samples and improve its limit of detection (LOD), the Double Pulse LIBS (DPLIBS) variant can be used instead of the standard Single Pulse LIBS (SP-LIBS), as it has been proven by several authors that DP-LIBS can considerably raise the analytical performances of the technique. In this work Mo samples coated with a 1.5-1.8 mu m thick W-Al mixed layer, contaminated with co-deposited deuterium (D) were measured by SP- and DP-LIBS under vacuum (p similar to 5 x 10(-5) mbar), with an experimental set-up simulating conditions that can be found in a real fusion device between plasma discharges. A partial Calibration Free procedure (pCF) was applied to the LIBS data in order to retrieve the relative concentration of W and Al in the mixed layer. The amount of deuterium was then inferred by using tungsten as internal standard, accounting for the intensity ratio between the D alpha line and nearby W I lines. The results are in satisfactory agreement with those obtained from preliminary Ion Beam Analysis measurements performed immediately after the specimen's realization. (C) 2017 Elsevier B.V. All rights reserved.

Laser-induced breakdown spectroscopy; LIBS; liquid; plasma; laser ablation;AQUEOUS-SOLUTIONS; VEGETABLE-OILS; WASTE-WATER; LIBS; METALS; ELEMENTS; SODIUM; PLASMA; PULSE; ACIDS

We studied changes in laser-induced breakdown spectroscopy (LIBS) signal intensity with the thickness of a liquid layer placed on a solid substrate, where an easily evaporating methanol sample was used. For a certain optimal liquid film thickness we obtained a manifold increase of the LIBS signal from methanol. Progressive liquid film thinning leads to a reduction and a successive disappearance of laser-induced splashes; the latter condition drastically reduces the sample consumption and allows measurements to be repeated many times on a single liquid droplet. In following, we developed two methods for actively controlled deformation, i.e., thinning of a liquid droplet (volume similar to 10 ml) prior to its sampling by LIBS. Control of the droplet's height was achieved on a Si-SiO2 wafer substrate by electro-wetting in the case of water solutions or by target rotation in the case of viscous liquids. The chosen substrate also has the advantages of low cost, easy manipulation, and very high purity, thus minimizing interference with analytes. Through the droplet deformation, in a single-pulse excitation at moderate laser energy (70 mJ), we clearly detected Fe and Mn in peanut oil, which represent trace elements in edible oils (similar to 1 part per billion), according to results published in the literature.