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Artistic surfaces at the Bishop’s Palace of Frascati have been investigated by an integrated approach involving different non-invasive technologies. Information on previous restoration actions are reported in this paper. © 2019 International Conference on Metrology for Archaeology and Cultural Heritage.

Laser Induced Fluorescence (LIF) is a well-recognized spectroscopic technique for non-destructive surface chemical analysis. It is particularly suitable for in situ analysis on delicate targets as artworks, because it does not need any sample preparation nor contact, working remotely also where only optical access is available. Hyperspectral systems have the advantage to provide whole spectra of the analysed point, and thanks to motorized optics can produce fluorescence images and map of surfaces. Since the early 2000s ENEA has developed hyperspectral LIF scanning systems. To shorten significantly analysis time, overall on very large CH surfaces as building facades, ENEA DIM Laboratory has developed an imaging multispectral LIF system. Here we present intercalibration, data analysis and software to automatically correct such imaging data and take into account filter’s bandpass and optical efficiencies with respect to systems based on the use of spectrometers, avoiding lack of selectivity and accuracy due to the absence of whole spectra.

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The provision of a particle and power exhaust solution which is compatible with first-wall components and edge-plasma conditions is a key area of present-day fusion research and mandatory for a successful operation of ITER and DEMO. The work package plasma-facing components (WP PFC) within the European fusion programme complements with laboratory experiments, i.e. in linear plasma devices, electron and ion beam loading facilities, the studies performed in toroidally confined magnetic devices, such as JET, ASDEX Upgrade, WEST etc. The connection of both groups is done via common physics and engineering studies, including the qualification and specification of plasma-facing components, and by modelling codes that simulate edge-plasma conditions and the plasma-material interaction as well as the study of fundamental processes. WP PFC addresses these critical points in order to ensure reliable and efficient use of conventional, solid PFCs in ITER (Be and W) and DEMO (W and steel) with respect to heat-load capabilities (transient and steady-state heat and particle loads), lifetime estimates (erosion, material mixing and surface morphology), and safety aspects (fuel retention, fuel removal, material migration and dust formation) particularly for quasi-steady-state conditions. Alternative scenarios and concepts (liquid Sn or Li as PFCs) for DEMO are developed and tested in the event that the conventional solution turns out to not be functional. Here, we present an overview of the activities with an emphasis on a few key results: (i) the observed synergistic effects in particle and heat loading of ITER-grade W with the available set of exposition devices on material properties such as roughness, ductility and microstructure; (ii) the progress in understanding of fuel retention, diffusion and outgassing in different W-based materials, including the impact of damage and impurities like N; and (iii), the preferential sputtering of Fe in EUROFER steel providing an in situ W surface and a potential first-wall solution for DEMO.

The expulsion of runaway electrons (REs) during different types of tokamak instabilities is analysed by means of a Cherenkov probe inserted into the scrape-off layer of the FTU tokamak. One such type of instability, the well-known tearing mode, is involved in disruptive plasma termination events, during which the risk of RE avalanche multiplication is highest. The second type, known as anomalous Doppler instability, influences RE dynamics by enhancing pitch angle scattering. Three scenarios are analysed here, characterised by different RE generation rates and mechanisms. The main conclusions are drawn from correlations between the Cherenkov probe and other diagnostics. In particular, the Cherenkov probe permits the detection of fast electron expulsion with a high level of detail, presenting peaks with 100% signal contrast during tearing mode growth and rotation, and sub-peak structures reflecting the interplay between the magnetic island formed by the tearing mode, RE diffusion during island rotation and the geometry of obstacles in the vessel. Correlations between the Cherenkov signal, hard x-ray emission and electron cyclotron emission reveal the impulsive development of the anomalous Doppler instability with instability rise time in the microsecond scale resolved by the high time-resolution of the Cherenkov probe.

In situ methods to measure the fuel retention and to characterize the material deposition on the wall are highly important for ITER and future fusion devices. Laser-based methods are the most promising candidates (for non-invasive applications) and their feasibility is assessed in a cooperative undertaking in various European associations under EFDA coordination. The work concentrates on three different laser techniques in which the laser light is guided from outside the biological shield by a mirror system through a window onto special wall areas: i) laser induced desorption spectroscopy (LIDS) in which ms laser pulses thermally desorbs the retained fuel from a wall area of about 1cm2 and this fuel is spectroscopically detected in the edge of a running plasma, ii) laser induced ablation spectroscopy (LIAS) in which ns laser pulses ablates material from a small wall spot and the ablated material together with the incorporated fuel is detected in a similar way as in LIDS and iii) laser induced breakdown spectroscopy (LIBS) in which ns (or even ps ) laser pulses produce in front of the irradiated wall spot a plasma plume which (in proper conditions) emits line radiation being a fingerprint of the chemical composition of the ablated materials. The aims are to compare the pros and cons of the methods and propose an optimized solution for ITER. LIDS and LIAS have been developed in the TEXTOR tokamak to a prototype-like status for application in ITER. LIBS has been investigated in several EU laboratories in dedicated lab experiments with a focus on the particular conditions in ITER, including pilot experiments in the TEXTOR tokamak. To enable a clear and fair quantification of the methods, standard deposits of diamond like carbon (DLC) and mixed W/Al/C (with Al mimicing Be) with thicknesses of 2-3 μm deposited on rough and polished W substrates with a known D inventory were prepared using magnetron sputtering and vacuum arc deposition. They were used as reference samples in studies

Tritium (T) inventory in Plasma Facing Components (PFCs) will be one of the critical issues for ITER because of the impact tritium can have on the machine operation and safety. Laser Induced Breakdown Spectroscopy (LIBS) is a promising technique to accomplish this task, providing both qualitative and quantitative composition of the chemical elements retained in PFCs. LIBS does not require sample pretreatment or manipulation, it can work in-situ between fusion discharges or during maintenance periods, it is suitable for measurements at different residual pressures, with different background gases. It can detect all the chemical elements through their spectral emission. This paper presents the results of LIBS measurements at 100 mbar nitrogen pressure on metallic coating (W-Al-D) simulating the superficial composition of ITER divertor PFCs contaminated with nuclear fuel and material eroded from the first wall. LIBS spectra showed clear W, Al, D emission lines. A quantitative estimation of their relative concentration was performed by applying the Calibration Free (CF) analysis. CF does not require reference samples, so it's particularly suitable for this purpose. CF results were compared with the nominal concentrations and were found in good agreement with the latter.

Nowadays scientific study of Cultural Heritage accompanies most of the time historical artistic evaluation and an assessment of the conservation state by humanistic experts and restorers. Several laboratory methods with high sensitivity are well established (ICP-MS, FTIR,…), and many methods for in situ rough characterization of large surface are widely diffused (thermovision, UV photography,…), in addition to instrumentation for punctual analysis to be applied also in field (XRF, colorimetry,…). However, the request for systems that can provide rapid detailed characterization on large surface in any storage conditions is still a hot topic. This is combined with the ever-increasing demand for digital material for documentation, fruition and study. Laser-based systems, and in particular Laser Induced Fluorescence (LIF), Laser Induced Breakdown Spectroscopy and Raman spectroscopy, due to the characteristics of these sources and the detectors to which they can be coupled, respond well to these needs. The TECFIS-DIM (Diagnostic and Metrology) Laboratory of the ENEA center of Frascati (Rome, Italy) in the last decade has put an effort to develop more and more compact and efficient laser systems for in situ material characterization on cultural heritage surfaces. Here two prototypal LIF systems have been used to characterize marble surfaces treated with ancient and modern materials and a rapid recognition and mapping method has been developed and tested thanks to the individuation of discriminant spectral features. Results are reported on test samples created in lab with known substances and in situ on real artworks.

Laser-induced fluorescence (LIF) is a powerful remote and non-invasive analysis technique that has been successfully applied to the real-time diagnosis of historical artworks. Hyperspectral images collection on fresco's and their false colours processing allowed to reveal features invisible to the naked eye and to obtain specific information on pigments composition and consolidants utilization, the latter also related to former restorations. This report presents the results obtained by ENEA LIF scanning system during a field campaign conducted in June 2010 on fresco's by Giusto de' Menabuoi in the Padua Baptistery. The data collected by LidArt allowed the detection of Paraloid B72 and Movilith/Primal AC33, guiding the restorers in their conservation actions. © 2013 Elsevier Masson SAS.

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 (DP-LIBS) 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 μm thick W-Al mixed layer, contaminated with co-deposited deuterium (D) were measured by SP- and DP-LIBS under vacuum (p ~ 5 × 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 Dα 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. © 2017 Elsevier B.V.

The aim of this archaeometric study is to recover information regarding technological processes and raw materials used for the production of ceramic sherds coming from five central and Eastern German sites, between Lower Saxony and Saxony states. The ceramic fragments have been investigated by a multi-spectroscopic approach: Fourier transform infrared spectroscopy (FT-IR), micro-Raman spectroscopy and X-ray Fluorescence (XRF) were employed to characterize both ceramic bodies and glazes. Moreover the innovative application of Laser Induced Fluorescence (LIF) on ceramic findings has been proposed and evaluated. Chemical and mineralogical composition, as well as microstructure, of ceramic mixture and glaze are correlated to native material composition and firing temperature, which have become a fundamental features in archaeometric research and play a key role in understanding the provenance of the pottery and its production techniques.The multi-spectroscopic approach applied in this work has enabled the ability to characterize the ceramic sherds and to investigate through non-destructive techniques both ceramic glaze and matrix giving information regarding the raw materials and pigments/colourants used, and regarding firing temperature and technology. The present study carried on using complementary methods suggests different raw material sources and temperature kilns. These data are in agreement with the location of ceramic sites and with data in literature. Furthermore, the interesting results suggest that non-destructive techniques, such as LIF and Raman spectroscopy, are promising methods for ceramic and glaze characterization. © 2015 Elsevier B.V..

Laser-induced fluorescence (LIF) has found, in the recent years, widespread application to the field of material study and characterization. In particular, LIF has been applied to the assessment of damage, biological growth, and the analysis of specific materials on various surfaces in cultural heritages. Only a few papers deal with the application of LIF to the study of modern synthetic materials (mostly plastics) and pigments, and the analysis of contemporary works of art. Preliminary laboratory measurements on a wide range of plastic and cellulose-based materials, solvents, resins, and varnishes have been performed for rapid material characterization during in situ measurement campaigns in cultural heritage, security, and forensic contexts. Four paintings by Gastone Novelli, in the National Gallery of Modern and Contemporary Art, Rome, have been investigated by a compact LIDAR fluorosensor scanning system developed at the Laboratory of Diagnostic and Metrology in the ENEA Centre of Frascati (UTAPRAD-DIM Laboratory) for LIF measurements. Results and the relative data processing have provided fluorescence images, false color images, and punctual spectral information. The comparison with data and spectra from purpose-built reference databases has enabled recognition of materials on the paintings, and provided information on their production. © The International Institute for Conservation of Historic and Artistic Works 2015.

The development of novel materials for energy harvesting applications or strain sensing has generated great interest towards zinc oxide (ZnO) nanostructures, and in particular towards the synthesis of ZnO nanowires or nanorods with well controlled morphology and properties. The high-yield mass production of such nanostructures by catalyst-free methods is a crucial aspect to enable a cost-effective large-scale development of new ZnO-based piezoelectric devices and materials. In the present work, we propose a method for the mass-production of high-purity ZnO-nanorods with a uniform size distribution, based on the combination of thermal decomposition of zinc acetate dihydrate and probe sonication in acetone. The quality of the produced ZnO nanorods is assessed through multi-technique characterization using field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and photo-luminescence spectroscopy (PL). The adopted synthesis method is simple, cost effective and feasible for large-scale production. Various process parameters such as precursor amount and growth time have been found to play an important role in controlling the formation of the as grown nanostructures with high uniformity in size and morphology. Size distribution curves were employed to depict the effect of various process parameters for tailoring the morphology, homogeneity and aspect ratio of the nanorods. Our results reveal that the high crystallographic quality of ZnO nanorods grown by a long-time thermal decomposition method is not affected by probe sonication, which is proposed as a post-synthesis step necessary to produce ZnO nanorod powder with a uniform distribution of diameters and lengths. © 2015 The Royal Society of Chemistry.

Optical and spectroscopic techniques offer unique possibilities for non destructive or micro-destructive characterization of surfaces, with widespread applications, starting from in-line monitoring of industrial processes. A significant group of industrial applications concerns nuclear grade material characterization and plasma diagnostics relevant to the thermonuclear fusion process. However, technologies and methodologies originally developed for specific in-vessel utilization, can easily find additional in-situ and remote application to environmental and cultural heritage (CH) diagnostics addressed to preventive conservation and restoration of surfaces. At ENEA Frascati different prototypes have been developed and patented to collect reflectance and fluorescence images excited at different ultraviolet and visible laser wavelengths, Raman and LIBS signals. Portable integrated instruments suitable for operation at different distances from a 1.5 to 30 m, have been assembled and operated in laboratory on multilayered samples and in field campaigns for Security and on CH painted surfaces. Significant results relevant to the cross fertilization among different applications will be presented and discussed.

High temperature plasma in hydrogen isotopes is peculiar of thermonuclear fusion devices. The study of plasma-wall interaction is of paramount importance for avoiding both damage of plasma facing components (PFCs) and pollution of the plasma. To assure continuous and fault-free operation a strict control must be exerted on the amount of impurities deposited on, and of the fuel retained in the PFCs. This requirement makes Laser-Induced-Breakdown-Spectroscopy (LIBS) an ideal candidate for on-line quantitative monitoring of the walls of the current as well as of the next generation fusion devices like the International Thermonuclear Experimental Reactor (ITER). An experimental setup has been designed and realized in order to optimize the characteristics of a LIBS system working at low pressure and remotely, and it has been utilized in combination with calibration free procedures for quantitative analysis. In this work, a partial calibration free method has been developed for single shot analysis of hydrogen isotopes retention at the PFCs-like surfaces, based on the acquisition of high resolution spectra in a narrow wavelength range. Results of calibration free and partial calibration free have been obtained on suitably deuterated samples; preliminary spectroscopic considerations on tritium detection are also presented. © 2013 Elsevier B.V. All rights reserved.

Scanning hyperspectral systems based on laser induced fluorescence (LIF) have been developed and realized at the ENEA allowing to obtain information of analytical and qualitative interest on different materials by the study of the emission of fluorescence. This technique, for a surface analysis, is fast, remote, not invasive and specific. A new compact setup capable of fast 2D monochromatic images acquisition on up to 90 different spectral channels in the visible/UV range will be presented. It has been recently built with the aim to increase the performances in terms of space resolution, time resolved capabilities and data acquisition speed. Major achievements have been reached by a critical review of the optical design. The results recently obtained with in-situ measurements of interest for applications in the field of cultural heritage will be shown. © 2001 Elsevier Science. All rights reserved

The study of plasma-wall interactions is of paramount importance for continuous and fault free operations in thermonuclear fusion research to monitor the damages of plasma facing components (PFCs), plasma pollution from impurities and wall retention of hydrogen isotopes, like tritium. These needs make laser-induced-breakdown-spectroscopy (LIBS) a suitable candidate for a real time monitoring of PFCs in the current and next generation fusion devices, like ITER. It is also worthwhile for the quantitative analysis of surfaces, with micro-destructivity of the sample and depth profiling capabilities with sub-micrometric sensitivity. In this paper LIBS spectroscopy is exploited as a valid diagnostic tool for PFCs at the ENEA Research Center in Frascati (Italy) and at the Institute of Plasma Physics and Laser Microfusion (IPPLM) of Warsaw (Poland). The activities have been focused on LIBS characterization of samples simulating PFCs surfaces eroded/redeposited or contaminated from nuclear fuel after or during the normal operation of the reactor. © 2016 The Royal Swedish Academy of Sciences.

In this work, the effectiveness of nanocomposite surface treatments as protective systems for artistic stones was evaluated. Pyrolitic silica and titania nanoparticles were dispersed in a commercial silicon-based polymer and applied on marble and travertine samples. Artificial aging processes, both in climatic chamber and in solar box, were carried out to simulate real degradation processes in terms of photo-thermal effects and physical-chemical damage. The performances of the nanocomposites used as consolidant were evaluated comparatively by means of diverse diagnostic techniques, namely: scanning electron microscopy (SEM), laser induced fluorescence (LIF), ultrasonic technique, colorimetry, total immersion water absorption and contact angle. The results show that some properties of conservation materials can be improved by the presences of nanoparticles because they induce substantial changes of surface morphology of the coating layer and counter the physical damage observed during artificial weathering. © 2014 AIP Publishing LLC.

Laser Induced Breakdown Spectroscopy (LIBS) is a potential candidate to monitor the layer composition and fuel retention during and after plasma shots on specific locations of the main chamber and divertor of ITER. This method is being investigated in a cooperative research programme on plasma devices such as TEXTOR, FTU, MAGNUM-PSI and in other various laboratorial experiments. In this paper LIBS results from targets of D-H-rich carbon films and mixed W-Al-C deposits on bulk tungsten substrates are reported (simulating ITER-like deposits with Al as proxy for Be). Two independent methods, one to determine the relative elemental composition and the other the absolute contents of the target based on the experimental LIBS signals are proposed. The results show that LIBS has the capability to provide the relative concentrations of the elements on the deposited layer when the experimental conditions on the targets surface are identical to the calibration samples. © 2013 Elsevier B.V. All rights reserved.