Francesco Grazzi

Neutron diffractometer INES for quantitative phase analysis of archaeological objects.

With the Italian Neutron Experimental Station (INES) a new general purpose neutron powder diffractometer is available at ISIS, characterized by a high resolution at low d-spacings, and particularly suited for the quantitative phase analysis of a wide range of archaeological materials. Time-of-flight neutron diffraction is notable for being a non-destructive technique, allowing a reliable determination of the phase compositions of multiphase artefacts, with or without superficial corrosion layers. A selection of archaeometric studies carried out during the first year of the INES user programme is presented here to demonstrate the capabilities of the instrument.

Quantitative characterization of Japanese ancient swords through energy-resolved neutron imaging

Japanese blades are culturally interesting objects both from the stylistic point of view and because of their fantastic performance. In this work, we present new results, using a non-invasive approach, concerning these peculiar artefacts. Five Japanese swords pertaining to Koto (987–1596) and Shinto (1596–1781) periods have been analysed through white beam and energy resolved neutron-imaging techniques. The experiments have been performed at the ICON beam line, operating at the spallation neutron source SINQ, Paul Scherrer Institut in Switzerland. The reconstruction of projection data into neutron tomographic slices or volumes allowed us to identify some peculiar characteristics, related to the forging methods that were used by the different schools and traditions in Japan.

From Koto age to modern times: Quantitative characterization of Japanese swords with Time of Flight Neutron Diffraction

Japanese blades have always been considered very interesting objects, both from the stylistic point of view and their peculiar performances. It is amazing how the test and try process with a semi-empirical approach which lead to the optimization of Japanese blades, an almost ideal tool, is yet to be fully understood. In this work, we present results from a new non invasive approach to the study of these peculiar artefacts. Time of Flight Thermal Neutron Diffraction (TOF-ND) measurements were taken on two instrument INES and ENGIN-X, at the ISIS facility, RAL, UK. Two Japanese blades and eight blade fragments have been successfully characterized in terms of composition of the steel, smelting and smithing processes, and forging techniques. The differences among the production periods and forging traditions have been clearly determined. Further work is needed on standards to fully understand the production technique of a sample by comparison of the object under study with objects of known production methods.

A neutron imaging device for sample alignment in a pulsed neutron scattering instrument

A neutron-imaging device for alignment purposes has been tested on the INES beamline at ISIS, the pulsed neutron source of Rutherford Appleton Laboratory (U.K.). Its use, in conjunction with a set of movable jaws, turns out extremely useful for scattering application to complex samples where a precise and well-defined determination of the scattering volume is needed.

Non-invasive quantitative phase analysis and microstructural properties of an iron fragment retrieved in the copper-age Selvicciola Necropolis in southern Tuscia

This work presents the non-invasive analysis, through time of flight neutron diffraction, of a unique grey metal ferrous artefact in the shape of an awl. This object was found together with other copper samples in the Selvicciola Necropolis, which includes 34 eneolithic underground tombs, dated radiometrically between halfway through the fourth millennium and the end of the third millennium BC. The sample was originally covered with mineralization products. However, its main peculiarity resided in an almost total absence of rust. The uniqueness of such a sample imposed a non-invasive approach for its analytical study. In addition, being a singular object, in that environment, its study was considered mandatory to better understand the metallurgical skills of a copper-age community in central Italy. Thermal neutron scattering techniques have provided a wealth of information about the composition, the smelting process, and the mechanical and thermal treatments applied during the manufacture of the sample. The results obtained suggest that the sample had been treated according to the typical approach used for copper alloy smelting and smithing, i.e. cold working at room temperature and annealing at ∼700 to 800 °C.

An apparatus for simultaneous thermodynamic and optical measurements, with large temperature excursions

We report the design and realization of an integrated system for measuring, at the same time, the thermodynamic and spectroscopic features of nanoporous materials interesting for hydrogen storage purposes. The whole investigation cycle, from thermal activation to the actual investigation of uptake and release of hydrogen, is carried out in the same vacuum tight vessel, equipped with an optical window, whose temperature can range between 10 and 750 K, up to a maximum pressure of 50 bars. The system has been designed to investigate properties of carbon nanotubes but its use can be extended to any kind of nanoporous sample such as, for example, carbon nanofibers, zeolytes, metal organic frameworks, and similar materials.

Simultaneous and integrated neutron-based techniques for material analysis of a metallic ancient flute

A metallic 19th century flute was studied by means of integrated and simultaneous neutron-based techniques: neutron diffraction, neutron radiative capture analysis and neutron radiography. This experiment follows benchmark measurements devoted to assessing the effectiveness of a multitask beamline concept for neutron-based investigation on materials. The aim of this study is to show the potential application of the approach using multiple and integrated neutron-based techniques for musical instruments. Such samples, in the broad scenario of cultural heritage, represent an exciting research field. They may represent an interesting link between different disciplines such as nuclear physics, metallurgy and acoustics.

Non-invasive characterization through X-ray fluorescence and neutron radiography of an ancient Japanese lacquer

Oriental lacquer artefacts represent very interesting objects of investigation, involving a huge variety of materials and manufacturing techniques. Lacquers are very attractive not only for their stylistic features but also for understanding the variety of production processes, time evolution, use and artistic applications involved in their manufacturing. Till recently, the research activity on these materials has been mainly based on standard, more or less invasive, analytical methods. With the aim to characterise a nineteenth century Japanese lacquer in a totally non-invasive and non-destructive way, in situ X-ray fluorescence (XRF) and neutron radiography (NR) have been employed. While XRF suggested an identification of the pigments embedded into superficial layers, NR allowed revealing, in a single measurement, the average bulk properties of the sample.

Non Destructive Characterization of Phase Distribution and Residual Strain/Stress Map of Two Ancient (Koto) Age Japanese Swords

Two Japanese long swords (katanas) belonging to the Koto Age (X-XVI century A.D.) were measured through time of flight neutron diffraction to analyze the phases, and the stress and strain distribution, in selected parts of the blades. The swords are representative of two different forging schools (Aoe and Kanesada) and one of the main aims of the measurements was to evidence possible similarities and differences. Two independent experiments were carried out at the ISIS pulsed neutron source using the INES and ENGIN-X diffractometers. The former was employed to map the average phase distribution on two selected cross sections, of each blade, distinguishing among the ridge, the core, and the edge of the blades. In this way, we were able to quantify the coarse distribution of the carbon content and, moreover, we could evidence the presence of martensite. These data were then complemented measuring detailed stress and strain distribution maps on ENGIN-X. As far as the ridge and the core are concerned, the tang data were taken as a reference. These measurements significantly improve the knowledge and understanding of the technology used to produce Japanese swords belonging to the Koto Age.

A Neutron Resonance Capture Analysis Experimental Station at the ISIS Spallation Source

Neutron resonance capture analysis (NRCA) is a nuclear technique that is used to determine the elemental composition of materials and artifacts (e.g., bronze objects) of archaeological interest. NRCA experiments are mostly performed at the GELINA facility in Belgium, a pulsed neutron source operating with an electron linear accelerator. Very intense fluxes of epithermal neutrons are also provided by spallation neutron sources, such as the ISIS spallation neutron source in the United Kingdom. In the present study, the suitability of the Italian Neutron Experimental Station (INES) beam line for NRCA measurements is assessed using a compact (n, γ) resonance detector made of a Yttrium–Aluminum–Perovskite (YAP) scintillation crystal coupled with a silicon photomultiplier (SiPM) readout. The measurements provided a qualitative recognition of the composition of the standard sample, a lower limit for the sensitivity for NRCA for almost-in-traces elements, and an estimation of the relative isotopic concentration in the sample.