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The forensic scenario, on which the round robin study was based, simulated a suspected intentional manipulation of a real estate rental agreement consisting of a total of three pages. The aims of this study were to (i) establish the amount and reliability of information extractable from a single type of evidence and to (ii) provide suggestions on the most suitable combination of compatible techniques for a multi-modal imaging approach to forgery detection. To address these aims, seventeen laboratories from sixteen countries were invited to answer the following tasks questions: (i) which printing technique was used? (ii) were the three pages printed with the same printer? (iii) were the three pages made from the same paper? (iv) were the three pages originally stapled? (v) were the headings and signatures written with the same ink? and (vi) were headings and signatures of the same age on all pages? The methods used were classified into the following categories: Optical spectroscopy, including multispectral imaging, smartphone mapping, UV-luminescence and LIBS ; Infrared spectroscopy, including Raman and FTIR (micro-)spectroscopy ; X-ray spectroscopy, including SEM-EDX, PIXE and XPS ; Mass spectrometry, including ICPMS, SIMS, MALDI and LDIMS ; Electrostatic imaging, as well as non- imaging methods, such as non-multimodal visual inspection, (micro-)spectroscopy, physical testing and thin layer chromatography. The performance of the techniques was evaluated as the proportion of discriminated sample pairs to all possible sample pairs. For the undiscriminated sample pairs, a distinction was made between undecidability and false positive claims. It was found that none of the methods used were able to solve all tasks completely and/or correctly and that certain methods were a priori judged unsuitable by the laboratories for some tasks. Correct results were generally achieved for the discrimination of printer toners, whereas incorrect results in the discrimination of inks. For the discrimination of paper, solid state analytical methods proved to be superior to mass spectrometric methods. None of the participating laboratories deemed addressing ink age feasible. It was concluded that correct forensic statements can only be achieved by the complementary application of different methods and that the classical approach of round robin studies to send standardised subsamples to the participants is not feasible for a true multimodal approach if the techniques are not available at one location.

Cultural Heritage objects located in turbulent areas with a significant risk of terrorist attacks or inside a war zone are at risk of suffering damages similar to those in scenarios of severe seismic events, which are associated with partial or total building collapse and the subsequent need for monitoring, consolidation and successive reconstruction. To this end the availability of digital data collected by optical and spectroscopic laser scanners before the catastrophic event and stored as digital high resolution 2D and 3D maps can be a unique valuable support for future reconstruction. Conversely, continuous fiber glass monitoring may ensure reference data to evaluate the event impact and aid in planning consolidation. Examples of successful application of high-performance ENEA laser scanner prototypes in central Italy on monuments exposed to severe seismic risk are reported so as to illustrate the importance of storing quality 3D optical data before the event. The importance of fiber sensor monitoring during and after a seismic event in the same area is also shown from the collected data. Different examples of 3D reconstructions based on optical and spectroscopic data obtained within regional projects dealing with archaeological fragments (Roman frescoes and relief sculpture) are discussed, as regards their use in reconstructing from fragments in the aftermath of a catastrophic event.

Atmospheric aerosols are freely-moving multidimensional stochastic systems within a representative volume of air. Light-based techniques has proved to be a reliable and versatile tools for the direct, in-situ, real-time and remote gathering of information from aerosols in the atmosphere. However, acquiring analytical information is not trivial since particulate matter usually exhibits a broad compositional variability and a wide disparity of physical properties. In order to deeply scrutinize the performance of the laser induced plasma analysis of aerosols, here generated at distance of 10 m, side-viewed images of plasmas have been captured concurrently with their collinearly-acquired optical emissions. The plasma was induced by nanosecond laser pulses at a wavelength of 1064 nm on aerosols containing NaCl dissolved in water, and sprayed at different pressures. The photography reveals that the plasma consists of a series of luminous discharges, whose number, spatial distribution, size and luminosity, vary considerably with the particles size and salt concentration. The effects of the abundance and nature of luminous discharges composing the ongoing plasma on the intensity of the characteristic emission lines within the LIBS spectra have been discussed.

In this study, the feasibility of measuring the Sb content in different plastic materials by laser induced plasma spectroscopy (LIBS) is explored. Measurements were performed initially on a sample of pure Sb in order to identify the most prominent element transitions before different consumer plastics of varying matrix, composition and color were examined. The experimental set-up was based on a single pulse laser excitation at 1064 nm and a detection system consisting of an array of three compact spectrometers covering the range 236-796 nm. On pure Sb material, many atomic lines, particularly intense in the UV region, were observed, together with much weaker ionic transitions mainly in the visible spectral region. Unfortunately, all of the strong Sb transitions partially overlapped with those from Si, Fe and Ti, elements common in many plastic materials. For constructing the calibration curve for Sb content we exploited the Sb concentration values obtained by X-ray fluorescence (XRF) spectrometry, which varied from the detection limit (∼200 ppm) up to 65000 ppm. The analytical Sb I line at 276.99 nm was selected because, even if it has a weak contribution from one Fe I transition, its empirical subtraction leads to a well-correlated linear calibration graph. The corresponding detection limit was around 1400 ppm while in the absence of Fe, having an intense ionic transition at 259.93 nm, it is possible to use a more intense Sb I transition at 259.81 nm, achieving sensitivity on the order of 100 ppm. © 2018 The Royal Society of Chemistry.

In this work we report on the Laser-Induced Breakdown Spectroscopy (LIBS) characterization of the Frascati Tokamak Upgrade (FTU) first wall (FW) and toroidal limiter after the spring-summer 2019 experimental campaign. We performed our analysis by using a compact LIBS system mounted on the FTU robotic arm, entering the FTU vacuum vessel (VV) and measuring the FW elements in-situ. The LIBS system was expressly designed and developed for this task and, to our knowledge, it represents the first prototype of LIBS mounted on a robotic arm for analyses inside a tokamak. It allows to perform measurements at (1) atmospheric pressure or (2) in vacuum (down to 10−2–10−3 mbar) or (3) under gas flux (He, Ne, Ar etc.) and is suitable for 4) single pulse or 5) double pulse LIBS measurements. The LIBS analyses revealed the main chemical components of the stainless-steel FTU FW, Mo and Ti from the Titanium-Zirconium-Molybdenum alloy (TZM) tiles of the toroidal limiter. A superficial contamination of Li, originating from past liquid lithium limiter experiments was also clearly revealed. To simulate a LIBS analysis of a component of the ITER divertor region we placed a metallic sample at the bottom of the FTU VV through a sample holder and we measured it with the LIBS system. The stratigraphy of this ITER-like sample, composed of an Al/D superficial layer 3 μm thick (D 5% atomic concentration, Al as proxy for Be) on a W substrate simulates ITER PFCs in the divertor baffle and was characterized with high axial resolution (few hundreds nm for each laser shot) although the D signal from the Dα emission line at 656.1 nm was found strongly interfering with the corresponding Hα emission at 656.28 nm from the environmental hydrogen.

Here, we describe an innovative Integrated Laser Sensor (ILS) that combines four spectroscopic techniques and two vision systems into a unique, transportable device. The instrument performs Raman and Laser-Induced Fluorescence (LIF) spectroscopy excited at 355 nm and Laser-Induced Breakdown Spectroscopy (LIBS) excited at 1064 nm, and it also detects Laser Scattering (LS) from the target under illumination at 650 nm. The combination of these techniques supplies information about: material change from one scanning point to another, the presence of surface contaminants, and the molecular and elemental composition of top target layers. Switching between the spectroscopic techniques and the laser wavelengths is fully automatic. The instrument is equipped with an autofocus, and it performs scanning with a chosen grid density over an interactively-selected target area. Alternative to the spectroscopic measurements, it is possible to switch the instrument to a high magnification target viewing. The working distances tested until now are between 8.5 and 30 m. The instrument is self-powered and remotely controlled via wireless communication. The ILS has been fully developed at ENEA for security applications, and it was successfully tested in two outdoor campaigns where an automatic recognition of areas containing explosives in traces had been implemented. The strategies for the identification of nitro-compounds placed on various substrates as fingerprints and the results obtained at a working distance of 10 m are discussed in the following.

Laser-induced breakdown spectroscopy (LIBS) was tested for all of the relevant issues in forensic examinations of commercial inks, including classification of pen inks on one paper type and on different paper types, determination of the deposition order of layered inks, and analysis of signatures and toners on one questioned document. The scope of this work was to determine the potential of a single LIBS setup that is compatible with portable instruments for different types of ink analysis, rather than building a very large database for inks and papers. We identified up to seven metals characteristic for the examined inks, which allowed to fully discriminate all eight black inks on one type of printing paper. When the inks were tested on ten different papers, the correct classification rates for some of them were reduced for reasons thoroughly studied and explained. The replicated tests on three crossing points, each one involving a pair of blue or black inks, were successful in five cases out of six. In the test simulating documents of forensic interest (questioned documents), LIBS was able to correctly identify the differences in three inks used for signatures on one of the three pages and the use of different printing inks on each page of the document.

Droplets of organic liquids on aluminum substrate were probed by an Nd:YAG laser, both in a steady state and during rotation at speeds 18–150 rpm. Rotation transforms the droplet into film, which estimated thickness at high speeds was below 3 μm and 20 μm for diesel and peanut oil, respectively. Line intensities from the liquid (C I) and the support (Al I) material were tracked as a function of the film thickness and the laser energy. By film thinning, the line intensities from liquid sample were enhanced up to a factor 100x; simultaneously, the LIBS signal fluctuations were reduced 5–10 times with respect to the steady droplet. In certain experimental conditions, the line intensities from the support material become very weak with respect to the C I line, indicating an efficient screening of the substrate by highly excited plasma from the liquid layer. At a fixed rotation speed, there is a laser energy threshold, dependent on the liquid thickness, above which the LIBS signal becomes stable. Here, we discuss the relative processes and optimization of the experimental conditions for the LIBS measurements frome one laser shot to another.

Laser-induced breakdown spectroscopy (LIBS) measurements were performed on bulk water solutions by applying a double-pulse excitation from a Q-Switched (QS) Nd:YAG laser emitting at 1064 nm. In order to optimize the LIBS signal, laser pulse energies were varied through changing of the QS trigger delays with respect to the flash-lamp trigger. We had noted that reduction of the first pulse energy from 92 mJ to 72 mJ drastically improves the signal, although the second pulse energy was also lowered from 214 mJ to 144 mJ. With lower pulse energies, limit of detection (LOD) for Mg in pure water was reduced for one order of magnitude (34 ppb instead of 210 ppb). In order to explain such a phenomenon, we studied the dynamics of the gas bubble generated after the first laser pulse through measurements of the HeNe laser light scattered on the bubble. The influence of laser energy on underwater bubble and plasma formation and corresponding plasma emission intensity were also studied by photographic technique. From the results obtained, we conclude that the optimal first pulse energy should be kept close to the plasma elongation threshold, in our case about 65 mJ, where the gas bubble has its maximum lateral expansion and the secondary plasma is still well-localized. The importance of a multi-pulse sequence on the LIBS signal was also analyzed, where the pulse sequence after the first QS aperture was produced by operating the laser close to the lasing threshold, with the consequent generation of relaxation oscillations. Low-energy multi-pulses might keep the bubble expansion large prior to the probing pulse, but preventing the formation of secondary weak plasmas in multiple sites, which reduces the LIBS signal. The short interval between the pre-pulses and the probing pulse is another reason for the observed LIBS signal enhancement.

Laser Induced Breakdown Spectroscopy (LIBS) was applied on sediments directly under water. The aim of the research was to develop a method for measuring the sediment elemental composition, including minor elements, which could be implemented in-situ. The plasma was generated by a double-pulse, Q-Switched Nd:YAG laser operated at 1064 nm. For signal detection, both ICCD and non-gated, compact detectors were used. The major difficulties in underwater sediment analyses are related to the natural and laser induced surface roughness, and to the sample softness. The latter is responsible for the formation of particle clouds above the surface, which scatter both the laser and plasma radiation, and often results in breakdown formation above the analyzed surface. In such cases, a broad sonoluminescence emission from water, formed during the gas bubble collapse was sometimes registered. Under optimized experimental conditions, even by using a non-gated detector and single shot acquisition, it was possible to detect several minor sediment constituents, such as titanium, barium, manganese and others. A crude estimation of the Limit of Detection (LODs) for these elements was performed by underwater measurements on certified soils/sediments. Due to strong shot-to-shot fluctuations in the plasma temperature, well correlated calibration curves, aimed for quantitative analyses, could only be obtained after applying an appropriate data processing procedure. The latter selects automatically only the spectra characterized by similar plasma parameters, which are related to their continuum spectral distribution. Application of such a procedure improves the measurement accuracy also in other surroundings and on samples different from the ones analyzed here.

The optimal experimental conditions for quantitative analyses of the Martian similar crust by Laser Induced Breakdown Spectroscopy (LIBS) were studied comparatively in the air at atmospheric pressure and under the simulated planet atmosphere. Different laser energies were applied and the plasma dynamic, in terms of the emission intensity, temperature and electron density, were studied. The choice of the best experimental parameters includes: acquisition delay from the laser pulse and gate where the conditions of Local Thermal Equilibrium (LTE) holds, as necessary for the quantitative analyses, and further optimisation of the same parameters, as well as of the shot number, in order to maximize signal-to-noise ratio (S/N). Preliminary results demonstrate that for the same laser energies in a rarefied CO2 atmosphere the acquisition window where LTE conditions hold is much shorter than in the air due to the low electron density, fast plasma cooling and decay, where the last is the cause for even shorter optimum interval for maximizing S/N.

Laser induced breakdown spectroscopy (LIBS) has significant potential for remote terrestrial and extraterrestrial applications, nonetheless a number of correlated problems are still to be properly understood and possibly solved. This study focuses on several samples of terrestrial provenience, mostly volcanic rocks, which have importance as analogue to expected Martian samples. They were analysed after vaporisation with a frequency tripled Nd:YAG laser emitting at 355 nm , and measurements were made in an environment similar to the Martian one. Quantitative data were obtained by adopting the calibration free LIBS approach. A comparison with SEM-EDX data from the same samples is reported. Present results on Mars rocks analogues suggest that, in spite of residual interpretative ambiguities, LIBS technique permits elemental qualitative identification and quantitative analysis on silicate minerals examined in a rarefied atmosphere.

Single and double pulse laser-induced breakdown spectroscopy (LIBS) was carried out on aluminum samples in air. In the case of double pulse excitation, experiments were conducted by using the same laser source operated at the same wavelength (1064 nm in most cases here presented). A lowering of the second pulse plasma threshold was observed, together with an overall enhancement in line emission for the investigated time delay between the two pulses (40–60 μs). The laser-induced plasma originated by a single and double pulse was investigated near ignition threshold with the aim to study possible dynamical mechanisms in different regimes. Currently available spectroscopic diagnostics of plasma, such as the line broadening and shift due Stark effects, have been used in the characterization in order to retrieve electron densities, while standard temperature measurements were based on Boltzmann plot. Plasma relevant parameters, such as temperature and electron density, have been measured in the plasma decay on a long time scale, and compared with crater shape (diameter and inferred volume). The comparison of double with single pulse laser excitation was carried out while keeping constant the energy per pulse; the influence of laser energy was investigated as well. Results here obtained suggest that use of the double pulse technique could significantly improve the analytical capabilities of LIBS technique in routine laboratory experiments.

In the present work, we report on the analyses of different types of artworks, such as medieval glazed Umbrian pottery and copper based alloys from Roman and modern periods, performed by means of Laser Induced Breakdown Spectroscopy (LIBS). The semi-quantitative analyses on the multi-layered ceramic findings regard glaze, luster and pigment decorations present on the surface. The composition for each decorative layer was determined by estimating the contribution of the ceramic layer beneath the examined one to the whole plasma emission. Two types of ancient luster have been considered: red and gold, while the pigments examined include painted decorations of different blue tonalities. The measured elemental composition of the decorative layers resulted partially correlated with the color of the painted surface, measured by a standard UV-VIS spectrometer. In LIBS analyses of bronze samples, a procedure was developed, which improves data repeatability and extends quantitative measurements to minor elemental constituents. Results of the quantitative analyses gave indications about the manufacturing process of the artwork, its actual degree of conservation and the presence of residual surface decorations.

Laser induced plasma formation on or inside liquids is characterized by large energy losses due to liquid evaporation. Ablation of a liquid surface is followed by hydro-dynamical instabilities and splashing. Plasma generation inside bulk liquids is affected by the light absorption and scattering, and it is accompanied by intense pressure waves and successive vapor cavitation. Efficient LIBS analyses in presence of liquids require different considerations; the examples are reported and discussed in following.

With the aim to study alteration processes of the rock hewn churches from Lalibela (Ethiopia), we applied Laser Induced Breakdown Spectroscopy (LIBS) technique to measure the elemental composition both of the bulk rock materials and their external layers, exposed to the environmental factors. The analytical plasma was generated by nanosecond pulses of an Nd: YAG laser emitting at 1064 nm. Different major and minor sample constituents were detected, including Ca, Mg, Na, Fe, Ti, Al and K. The detected O emission originates both from air surrounding and the sample, while the intensity of N lines, coming exclusively from air, was used for the LIBS signal normalization. By depth profiling of the weathered basalt rock, we observed a lower presence of K in the external layers, corresponding to the first 5 laser shots. The emission from this element is anti-correlated with the line intensities from O, and this was attributed to the variations in relative abundances of clay minerals and K-feldspar. The analogue measurements were performed on the tuff rock, and compared to the spectra from powder samples containing only the external soft material, scratched from the rocks. These analyses show an abundance of H in the weathered, wetted layers and suggest that cations are lost from the constituent primary minerals and replaced by H+; this process disrupts the lattice structure and causes a marked loss of strength. The studies presented here demonstrate that LIBS is a useful technique for studying the alteration processes in the rocks, caused by environmental factors. © 2013 Elsevier Ltd.

The potential of a multi-pulse (MP) laser excitation scheme for deep stratigraphy of electrolytically galvanized steel using laser-induced breakdown spectrometry (LIBS) has been evaluated. For this purpose, a commercial electro-optically (EO) Q-switched Nd:YAG laser was employed, where by reducing the delay between the Q-switch opening and the flash lamp, a train of pulses (up to 11) separated by approximately 7.40 μs was generated during one lamp flashing. Plasma emission after each individual laser pulse of the MP sequence was detected by a spectrograph equipped with an intensified charge-coupled device (iCCD) detector. With MP excitation, the ablation efficiency was increased ten-fold on iron sample and 22.5-fold on zinc material with respect to dual-pulse or single-pulse excitation. The LIBS signal generated by MP excitation shows an analogous enhancement. Although the total energy per shot delivered to samples was only 60 mJ, it was possible using LIBS to measure the sample stratigraphy up to depths of 90 μm on zinc-coated steel sheets. A satisfactory agreement between the Zn thickness determined by the MP-LIBS system and data from the manufacturer has also been obtained.

Applications of Laser Induced Breakdown Spectroscopy (LIBS) for analysis of immersed solid and soft materials, and for liquid impurities are described. A method for improving the LIBS signal underwater and for obtaining quantitative analyses in presence of strong shot‐to‐shot variations of the plasma properties is proposed. Dynamic of the gas bubble formed by the laser pulse is also discussed, together with its importance in Double‐Pulse (DP) laser excitation. Results of the studies relative to an application of multi‐pulse sequence and its effects on the plasma and gas bubble formation are also presented.

Principles of the Laser Induced Plasma Spectroscopy and its advances are reported. Methods for obtaining quantitative analyses are described, together with discussion of some applications and the specific problems.

LIBS is one of the most promising techniques for rapid, in-situ elemental analyses of artworks. It does not require sample preparation, it is almost non destructive (micro sampling) and information both about major and trace elements could be obtained simultaneously. LIBS has been used to recognize the elements present in different archaeological materials and has been also proposed for on-line monitoring during the object cleaning by lasers. Quantitative determination of the material composition can supply useful information to restorers and help the object cataloguing. However, the analytical LIBS measurements on the archaeological materials were rarely reported, mainly due to difficulties to obtain the corresponding matrix-matched standards, required for the initial calibration. Alternatively, Calibration-Free (CF) approach could be used on some class of materials if all the major sample elements are detected and if the laser plasma preserves the material stochiometry. The latter condition is sometimes missing, as in the case of bronzes under nanosecond pulse laser ablation. We have developed a theoretical model for laser ablation of quaternary copper alloys, which allows for correction of the missing plasma stochiometry in CF approach. The model also predicts the optimal calibration for this type of material. In our recent work, we also obtained quantitative LIBS results on marbles by realizing the calibration standards starting from doped CaCO3 powders and by applying the corrections on the plasma parameters, different for the laboratory standards and marbles. Semi-quantitative LIBS results have been also obtained on multi-layered renaissance ceramics by subtraction of the contribution to plasma of each ceramic layer.

In this work laser-induced breakdown spectroscopy (LIBS) has been applied in bulk water using a double-pulse laser source. As in the case of former experiments in air, the use of the double-pulse technique allows for enhancing line emission intensity and reducing the duration of the continuum spectrum, thus increasing the overall analytical performances of the technique. Tap water analysis of Na and Mg dissolved cations has been performed to investigate the capability of the technique, but most significant results have been obtained in determining the composition of submerged bronze targets by laser ablation of their surface in seawater. When the plasma is generated by double-pulse laser, the ablated matter is strongly confined by the water vapor inside the cavitations bubble. The confinement of the plasma leads to higher values of excitation temperature and holds the conditions suitable for chemical analysis (homogeneity and LTE) longer than what happens in gaseous media. The double-pulse experiments performed directly in bulk water point out the features of LIBS technique for real analytical applications in situ, such as the water quality assessment and the investigation of irremovable submerged objects.

The use of laser ablation for cleaning stone is a tried-and-tested method for preserving outdoor artwork surfaces exposed to environmental stresses. However, it is of interest to spectroscopically characterize the sample surface before and during the laser ablation in order to implement automatic control of the cleaning process. To this aim, we have undertaken systematic LIBS analysis on various clean and dirty surfaces of marble fragments collected from ancient quarries in Mediterranean areas, without the characteristic patina that comes from the protective layers usually deposited on the final artwork. The effectiveness of the cleaning process was then monitored by following the disappearance from the LIBS spectra of the encrustation elements during successive laser shots. The LIBS analysis of the clean surfaces of the samples examined confirmed that main bulk composition is based on calcium and magnesium carbonates, with the addition of strontium and, to a minor extent, of manganese and copper substituents. On the other hand, the encrustations were rich in sodium, aluminum, iron, silicon, titanium, lithium, manganese, and chromium, probably coming from sand/soil deposition and, only to a minor extent, from atmospheric pollution. Although SEM imaging and SEM-EDX analyses performed on the same samples at different resolutions showed remarkable surface inhomogeneities from the crustal region deep into the bulk material, the work demonstrates the possibility of a quantitative, minimally invasive, LIBS stratigraphy. The results from the technique are suitable for monitoring cleaning processes by determining appropriate elemental markers present on the surface at trace level (of the order of 100 ppm).

White marble samples from ancient quarries have been analyzed by Laser Induced Breakdown Spectroscopy (LIBS) both on the bulk material and surface encrustations. With the aim to achieve quantitative results by LIBS, until now not reported on marble materials, calibration standards with CaCO3 matrices doped with certified soils were realized. Very different emission intensities and plasma parameters were observed on the standards and natural marbles. In order to compare so different spectra, a method for data analysis was developed, which takes into account variability of the ablation rate, plasma temperature and electron density. It was experimentally demonstrated that ablated volume is well correlated to the emission intensity of plasma continuum for a wide range of laser energies. LIBS signal normalization on the adjacent continuum level, together with introduction of correction factors dependent on plasma parameters, allowed the measuring of concentrations both for major and trace elements in marbles. The analytical procedure was validated by comparative SEM-EDX and ICP-OES measurements. Quantitative LIBS analyses were also performed during encrustation removal and could be applied to control laser-cleaning processes. The quantification of metal contents in the encrustations supported the occurrence of sulfates in the outer layers exposed to environmental agents via a catalytic process.

In spite of difficulties in quantitative LIBS analysis on copper based alloys, the very low invasiveness of the technique strongly sustains attempts to use it with cultural heritage materials, including ancient bronzes. Analytical results obtained with calibration curves and a calibration free model are compared here on a set of ancient roman coins. An attempt is presented to monitor the laser ablation process on bronze coins and artificially aged standards during the cleaning. The double pulse technique showed that LIBS analytical results could benefit from synchronization between the UV laser sources used, respectively, for cleaning (266 nm) and for LIBS analysis (335 nm).

In the present work, we report the analyses of glaze and decorations present on the surface of Renaissance Umbrian pottery, performed by means of different spectroscopic and optical techniques. Two types of ancient lustre have been considered: red and gold, coming from Deruta and Gubbio. The time resolved laser induced fluorescence (LIF) signatures of the red and gold lustre were identified by applying a laser excitation at 355 nm. Laser induced breakdown spectroscopy (LIBS) technique was applied on all the ceramic layers, i.e. bisque, glaze, and both lustre and blue coloured decorations, to determine semi-quantitatively their elemental composition. The results of colorimetric measurements are also compared to the measured composition of decorative layers.

The amount of tritium (T) retained in plasma facing components (PFCs) and in-vessel structures has to be carefully monitored in ITER because of the limits fixed by safety issues. Laser-Induced-Breakdown-Spectroscopy (LIBS) is one of the eligible techniques for this task because it does not require any sample pre-treatment (or removal), it can work both in atmospheric pressure or in vacuum, with different background gases. LIBS can be set up both on a robotic arm entering the vacuum vessel or outside it, for analyses during shut-down periods or in-between plasma discharges. In this paper we describe a new, compact LIBS system, mounted on the Frascati Tokamak Upgrade (FTU) robotic arm, to perform measurements on ITER-relevant samples placed in the FTU mock-up. The samples, composed of thin layers (few μm) of W, Al, D, simulate the co-deposition of Be with T on ITER divertor tiles (Be and T are replaced by Al and D in the samples). W, Al, D emission lines has been clearly detected, both as major constituents or in trace quantities, with different background gases using a single laser pulse.