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The authors regret finding a mistake in colour labels of Fig. 3b. Please find attached the figure corrected. [Figure presented] The authors would like to apologise for any inconvenience caused.

This work presents the results of a National Italian Project (PRIN, period 2011-2014) aiming at the development of new methodologies for the conservation of bronze and gilded bronze artefacts. Fire-gilded bronze is a precious material, widely used for historical artworks as well as in architectural elements and often exposed to aggressive atmospheres. There, it suffers extensive corrosion damage, due to galvanic coupling between the underlying bronze and the thin, highly defective gilded layer. Protective surface treatments, monitoring methods by electrochemical sensors and controlled-microclimate open showcases can represent quite useful measures against bronze and gilded bronze degradation.

In questo lavoro viene presentata la sperimentazione condotta, nell’ambito di una tesi di Laurea Magistrale a Ciclo Unico in Conservazione e Restauro dei Beni Culturali, presso l’Istituto di Fisica Applicata “Nello Carrara” del Consiglio Nazionale delle Ricerche di Firenze, per valutate le potenzialità di diversi regimi laser Nd:YAG a 1064 nm: Short Free Running (30 - 110 μs) e Long Q-Switch a singolo, doppio e triplo impulso (120 ns distanziati tra loro da 40 µs). A tale scopo sono stati selezionati alcuni frammenti di manufatti lapidei, di diverso periodo storico, databili tra il XVII secolo a.C. e il XX secolo, che offrivano problematiche conservative di particolare interesse. La conoscenza di questi manufatti e delle fenomenologie di degrado presenti su di essi è stata approfondita attraverso l’impiego sinergico di diverse tecniche di indagine, a partire da quelle non distruttive, quali la Microscopia Raman, Riflettenza Vis-NIR e Misure Colorimetriche. Successivamente, sono stati condotti il prelievo e l’analisi di micro-campioni, studiati con l’ausilio della Microscopia Ottica, in luce visibile e fluorescenza, Microscopia Elettronica a Scansione (SEM) e Microanalisi chimica elementare EDS (Spettrometria RX a dispersione di energia). Sui manufatti selezionati sono state condotte delle prove di ablazione laser, utilizzando diverse modalità operative, al fine di individuare le soglie di danno e gli intervalli operativi di fluenza idonei e ponendo particolare attenzione alla valutazione l’efficienza del processo di pulitura. Gli effetti dell’irraggiamento e i diversi livelli di pulitura ottenibili sono stati valutati approfonditamente anche grazie all’ausilio di confronti colorimetrici e la realizzazione di cross section, osservate e analizzate tramite Microscopia Ottica ed Elettronica. Variando opportunamente le condizioni operative è stato possibile ottenere dei livelli di pulitura ottimali, nel rispetto delle complessità delle differenti superfici trattate, e vagliare tutte le possibili implicazioni dell’uso di un regime o di un altro, al fine di attuare un corretto, puntuale e selettivo intervento conservativo, specifico per i casi studio esaminati. I risultati ottenuti confermano le innumerevoli potenzialità di questa tecnica, il cui impiego è ormai consolidato nel settore del restauro, ma soprattutto evidenziano l’estrema importanza di disporre di diversi regimi di funzionamento, vista la grande variabilità delle condizioni operative ottimali in funzione della tipologia di degrado e di manufatto trattati.

Fluence (J/cm2) and reflectance are key parameters in pulsed laser ablation processes. The dynamics and rate of the material removal are strictly dependent on the energy dissipated into the material under irradiation, which is complementary to the reflected energy. Laser cleaning of artifacts of cultural interest is a well-known application of laser ablation, which significantly grew along the last decade. The Long Q-Switch Nd:YAG laser (1,064 nm, ?=120 ns) is one of the most used laser systems (Salimbeni et al., J Cult Herit 4(1):72-76, 2003; Cacciari et al. Chem 402(4):1585-1591, 2012; Siano et al., Appl Phys A 106(2):419-446, 2012). This is usually equipped with optical fiber beam delivery terminated with a handpiece including an imaging lens and a mechanical arrangement to vary the fiber-to-lens distance in order to suitably set the laser spot diameter at the target. In this way, skilled restorers can set the operating fluence according to the interaction phenomenology observed. Here, a novel laser handpiece equipped with optical sensors in order to monitor fluence at the target and its reflectance, as well as the optimum working distance, is presented.

Pulsed neutron beams available at the ISIS spallation source offer diverse possibilities for materials characterization using diffraction and imaging. In this paper we review a range of applications of the time-of-flight neutron diffraction for the characterization of phase transformation and residual stress states in industrially-relevant situations. The setup of the ENGIN-X instrument at ISIS is described, followed by a series of case studies based on the recently obtained results.

Quantum dots (QDs) are semiconductor nanocrystals emerging as a new class of fluorescent labels with large brightness, multi color fluorescence emission and resistance against photobleaching. Here we have used QDs as biological markers in an immunofluorescence approach.In this work GABA(A )receptors of rat cerebellar granule cells have been studied and in particular we have visualized the beta(2/3) and delta subunits in live cells. The results obtained were compared to those gathered with conventional probes.The images of the delta subunit in living cells appear to correspond to those expected for a subunit part of GABA(A)receptors mediating tonic inhibition in the granules cell bodies.

The laser cleaning problem of gold leaf gilded surfaces was investigated here. Preliminary irradiation tests carried out on pure gold leaf standards evidenced the crucial importance of the laser pulse duration for avoiding serious damages. Optimised pulse duration providing good cleaning results with negligible side eects was then selected and successfully used in the restoration of three Renaissance masterpieces.

The INES project was sponsored by the CNR Neutron Spectroscopy Advisory Committee, stressing the importance of realizing an Italian Neutron Experimental Station (INES) at the world most powerful pulsed neutron source (ISIS, Rutherford Appleton Laboratory, UK) and evidencing the strategic value that such a test station would assume in the field of applied sciences like, for example, chemistry, material science, Earth science, crystallography, and last, but not least, in the field of science applied to the study of cultural heritage artifacts.

The Italian Neutron Experimental Station INES, located at the pulsed neutron source ISIS (U.K.), is equipped with a general-purpose neutron diffractometer that was built with a special care aiming to focus its use on archaeometric measurements. In fact, the large sample volume allows to accommodate non standard samples in the neutron beam, the diffraction banks cover an angle of almost 180°, allowing to detect the presence of texture, and the high instrument resolution enables a detailed analysis of the peak shape, to obtain information on the casting process and/or the working techniques applied during the production phase. Thanks to the high penetration power of thermal neutrons, archaeometric measurements performed through neutron diffraction allow to determine bulk properties of the sample. Here, we describe the instrument structure and present some preliminary test measurements, on standard samples, to show the high level quality of the machine. In particu- lar, we will show some results of interest in archaeometallurgy like, for example, multiphase analysis of bronzes and quantitative detection of impurities.

Nel presente contributo, riportiamo una sintesi degli sviluppi interpretativi sulla tecnica di fusione delle formelle della Porta del Paradiso, formulata sulla base dei dati ricavati dall’esame obiettivo, dall’analisi delle leghe di nove delle dieci formelle principali, dalle radiografie della formella VIII (Storie di Giosué), dalla sperimentazione e da quanto già emerso nell’indagine metallurgica di primi anni ottanta.

Neutron strain scanning is a well-established experimental technique used to quantify residual stresses in industrial objects. Characteristic elastic strain profiles are introduced by manufacturing processes and by loads experienced during service. Here we report neutron strain scanning experiments on archaeological bronzes, aimed to identify their original manufacturing techniques. The specimens studied were a Picenan necklace from VI BC, and an Etruscan bucket handle from IV BC, exhibited at the Marches National Museum of Archaeology, Ancona, Italy. Time-of-flight neutron diffraction and transmission experiments were performed at the ENGIN-X instrument, Isis, United Kingdom. For the necklace, characteristic bending strain profiles and a small degree of preferred orientation indicated that the specimen has been cold worked. For the handle, broad diffraction peaks and highly distorted Bragg edges -typical of a columnar grain microstructure- suggested that this specimen was cast and did not undergo any significant thermal or mechanical treatment. The relation between the experimental diffracted and transmitted time-of-flight spectra, and the microstructure of a specimen are discussed in this paper.

Studio di bronzi archeologici con diffrazione di neutroni