Realisation and characterisation of Cu-based references for neutron imaging calibration purposes and first results

The long-term purpose of this study is to assess the capabilities of the new Neutron Imaging beamline developed at the LENA facility of Pavia (Italy) for the characterisation of bronze artefacts. In this preliminary work, a set of Cu-based reference alloys has been produced and analysed in order to test and calibrate the facility. The first step involved the production of Cu-based alloys with chemical composition and microstructure similar to ancient artefacts. The chemical composition of the reference alloys was analysed by Optical Emission Spectroscopy. Secondly, some samples were artificially patinated with different chemical treatments obtaining an artificial corrosion products layer comparable to natural corrosion. X-Ray Diffraction, Scanning Electron Microscopy and Raman Spectroscopy have been used to characterise the corrosion patina. The main corrosion products on sulphate-induced patina are cuprite and brochantite, whereas atacamite and clinoatacamite were detected on chloride-induced patinas. Finally, preliminary Neutron Imaging measurements were performed on a first set of coated and uncoated specimens in order to try to correlate the neutrons attenuation coefficients with the chemical compositions with promising results

Caratterizzazione di manufatti in ferro di epoca fenicio-punica mediante spettroscopia Raman

I manufatti archeologici metallici vanno incontro a naturale corrosione, sia durante l’interramento che dopo l’estrazione dallo scavo. Quando si studiano i meccanismi di corrosione, bisogna tener conto che sia la composizione iniziale del manufatto sia le condizioni di interramento hanno un ruolo fondamentale nella velocità e nel tipo di degrado del materiale. L’identificazione dei prodotti di corrosione, tendenzialmente ossidi ed idrossidi di ferro, permette di ipotizzare i meccanismi di degrado a cui è stato sottoposto il manufatto durante l’interramento in modo da pianificare trattamenti di consolidamento e di protezione. Nel presente studio, alcuni chiodi di età fenicio-punica provenienti dallo scavo archeologico di Tharros (Sardegna) sono stati analizzati mediante spettroscopia Raman al fine di caratterizzare i prodotti di corrosione del ferro

SCHEDA DI ACQUISIZIONE DATI A BASSO COSTO

Le schede di acquisizione dati (DAQ) prodotte dai principali costruttori ed utilizzate per le più svariate misurazioni, hanno un costo molto elevato e spesso non sono in grado di operare con diversi sistemi operativi. Questa memoria mostra come siano state progettate e realizzate due diverse DAQ che sono utilizzabili con praticamente qualsiasi sistema operativo e hanno con un costo molto inferiore rispetto alle schede commerciali, pur mantenendone la grande flessibilità e facilità di uso. Le DAQ qui descritte sono state realizzate in due versioni: nella prima versione la scheda è interamente implementata con un’unica scheda di sviluppo commerciale di costo molto ridotto di tipo Teensy; la seconda versione, invece, impiega alcuni componenti aggiuntivi (essenzialmente convertitori analogico/digitali) per ottenere prestazioni migliori. In entrambi i casi la connessione con il PC è ottenuta tramite l’interfaccia USB, ormai presente in ogni PC. Il software, che viene utilizzato con entrambe le schede è basato su Java, e, differentemente da molte DAQ commerciali, utilizzabile su praticamente tutti i sistemi operativi (ad esempio OSX, Windows e Linux) ed in tutte le versioni. Entrambe le schede DAQ proposte sono alloggiate in un contenitore, realizzato tramite una stampante 3D che rende semplice ed agevole l’uso delle schede stesse

Datation par ESR et ESR/U-Th de sites du Pleistocène Moyen d’Italie, comparaison avec l’40Ar/39Ar

International audienceLes séquences stratigraphiques de nombreux sites paléolithiques du centre et du sud de l'Italie, formé en contexte fluvio-lacustre et riches en vestiges archéologiques et paléontologiques, ont enregistré de nombreux événements volcaniques. Cette succession d’épisodes détritiques et volcaniques permet la comparaison des chronologies obtenues par la méthode ESR appliquée aux quartz fluviatiles blanchis optiquement, en utilisant les centres Al et Ti, par la méthode ESR/U-Th, appliquée à l'émail dentaire des vestiges paléontologiques, avec le cadre chronologique obtenu par la méthode de datation 40Ar/39Ar, appliquée quant à elle sur des cristaux de feldspaths potassiques.Depuis 2009, plusieurs sites du Pléistocène moyen, comprenant des niveaux volcaniques, fluviatiles et archéologiques ont ainsi été étudiés: Isoletta et Lademagne dans le Latium et Venosa Notarchirico en Basilicate.Les résultats obtenus, qui couvrent la plage de temps compris entre 700 et 350 ka, seront présentés et discutés. Ils indiquent que l'approche multiméthode est utile pour restreindre la chronologie de chaque site et que l'application de chaque méthode a des limitations spécifiques. Malgré ces limitations, nos résultats montrent que le cadre ESR et ESR/U-Th est globalement en accord avec la chronologie 40Ar/39Ar

ESR and ESR/U-series dating of several Middle Pleistocene Italian sites: a comparison with 40Ar/39Ar chronology

International audienceThe stratigraphic sequences of numerous palaeolithic sites of Central and Southern Italy, very rich in both archaeological and palaeontological remains, have recorded volcanic events allowing the comparison of the chronologies derived from ESR and ESR/U-series analyses on fluvial bleached quartz and tooth enamel respec-tively with the chronological framework obtained by 40Ar/39Ar dating method on single volcanic K-feldspar crystals. Since 2009, several Middle Pleistocene sites including volcanic and archaeological levels were studied (from the west to the east): La Polledrara di Cecanibbio, Isoletta, (Lazio), Guado San Nicola, Isernia La Pineta (Molise) and Venosa Notarchirico (Basilicata). The obtained results, that cover the time range between 660 and 350 ka, will be displayed and discussed. They indicate that the multi-method approach is useful to constrain the chronology of each site and that the application of every method have specific limitations due to the geological background (for ESR, the lack of quartz grains in some areas and for ESR/U-series complex U-uptake histories in others places). Despite these limitations, the ESR and ESR/U-series framework is globally in agreement with the 40Ar/39Ar chronology

Datation par ESR et ESR/U-Th de sites du Pleistocène Moyen d’Italie, comparaison avec l’40Ar/39Ar

International audienceLes séquences stratigraphiques de nombreux sites paléolithiques du centre et du sud de l'Italie, formé en contexte fluvio-lacustre et riches en vestiges archéologiques et paléontologiques, ont enregistré de nombreux événements volcaniques. Cette succession d’épisodes détritiques et volcaniques permet la comparaison des chronologies obtenues par la méthode ESR appliquée aux quartz fluviatiles blanchis optiquement, en utilisant les centres Al et Ti, par la méthode ESR/U-Th, appliquée à l'émail dentaire des vestiges paléontologiques, avec le cadre chronologique obtenu par la méthode de datation 40Ar/39Ar, appliquée quant à elle sur des cristaux de feldspaths potassiques.Depuis 2009, plusieurs sites du Pléistocène moyen, comprenant des niveaux volcaniques, fluviatiles et archéologiques ont ainsi été étudiés: Isoletta et Lademagne dans le Latium et Venosa Notarchirico en Basilicate.Les résultats obtenus, qui couvrent la plage de temps compris entre 700 et 350 ka, seront présentés et discutés. Ils indiquent que l'approche multiméthode est utile pour restreindre la chronologie de chaque site et que l'application de chaque méthode a des limitations spécifiques. Malgré ces limitations, nos résultats montrent que le cadre ESR et ESR/U-Th est globalement en accord avec la chronologie 40Ar/39Ar

ESR and ESR/U-series dating of several Middle Pleistocene Italian sites: a comparison with 40Ar/39Ar chronology

International audienceThe stratigraphic sequences of numerous palaeolithic sites of Central and Southern Italy, very rich in both archaeological and palaeontological remains, have recorded volcanic events allowing the comparison of the chronologies derived from ESR and ESR/U-series analyses on fluvial bleached quartz and tooth enamel respec-tively with the chronological framework obtained by 40Ar/39Ar dating method on single volcanic K-feldspar crystals. Since 2009, several Middle Pleistocene sites including volcanic and archaeological levels were studied (from the west to the east): La Polledrara di Cecanibbio, Isoletta, (Lazio), Guado San Nicola, Isernia La Pineta (Molise) and Venosa Notarchirico (Basilicata). The obtained results, that cover the time range between 660 and 350 ka, will be displayed and discussed. They indicate that the multi-method approach is useful to constrain the chronology of each site and that the application of every method have specific limitations due to the geological background (for ESR, the lack of quartz grains in some areas and for ESR/U-series complex U-uptake histories in others places). Despite these limitations, the ESR and ESR/U-series framework is globally in agreement with the 40Ar/39Ar chronology

ESR/U-series and ESR dating of several Middle Pleistocene Italian sites: Comparison with 40Ar/39Ar chronology

International audienceThe stratigraphic sequences of numerous Palaeolithic sites of Central and Southern Italy, very rich in both archaeological and palaeontological remains, have also recorded Pleistocene volcanic events through volcanic ash deposits (tephra). They allow the establishment of an accurate chronological framework by comparing results obtained by 40Ar/39Ar dating method on single volcanic K-feldspar crystals, with those derived from ESR and ESR/U-series analyses on fluvial bleached quartz and tooth enamel respectively.Since 2009, these three methods were hence applied on samples of several Middle Pleistocene sites of Central and Southern Italy including both volcanic and archaeological levels (from the west to the east): La Polledrara di Cecanibbio, Isoletta, (Latium), Guado San Nicola, Isernia La Pineta (Molise), Valle Giumentina (Abruzzo) and Venosa Notarchirico (Basilicata).The obtained results, covering a time range from 660 to 350 ka, prove that such a multi-method approach when possible is essential to constrain the chronology of each site and allow the recognition of the specific limitations due to the lack of quartz for ESR or to complex geochemical histories in teeth rendering difficult the ESR/U-series method. Despite these limitations, the ESR framework is globally in agreement with the 40Ar/39Ar chronology, while ESR/U-series dates can be underestimated for the oldest sites. In such cases, an isochron approach attests however of the quite good reliability of the palaeodosimetric reconstruction and the observed age underestimation could be related to other factors affecting the ESR age determination

Integrated geochronology of Acheulian sites from the southern Latium (central Italy): Insights on human-environment interaction and the technological innovations during the MIS 11-MIS 10 period

International audienc