Antonella Scherillo

Neutron resonance transmission imaging for 3D elemental mapping at the ISIS spallation neutron source

We demonstrate for the first time the viability of a three-dimensional (3D) elemental imaging technique based on Neutron Resonance Transmission Imaging (NRTI), which is a neutron technique based on the presence of a resonance structure in the neutron-induced reaction cross sections. These resonances allow the identification of elements and isotopes within an object in a non-destructive manner. A dedicated set-up on the INES (Italian Neutron Experimental Station) beamline of the ISIS spallation neutron source was employed for the experiments. An early mediaeval disc fibula from the Hungarian National Museum in Budapest was used for our demonstration. The methodology and analysis procedures are described and the results obtained from the reconstruction of the 3D NRTI elemental image of the ancient object are compared with the results obtained from other neutron-based 3D imaging techniques.

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.

Measurements of gamma-ray background spectra at spallation neutron source beamlines

The gamma-ray background spectra of VESUVIO and INES beamlines, at the ISIS spallation neutron source, were measured with an HPGe spectrometer. These measurements are intended to provide information on typical gamma-ray background spectra in spallation neutron source environments, with special regard to beamlines employing gamma-ray sensitive detectors. Sources and creation processes of more than 60 gamma-ray lines in the energy range 80 keV–12 MeV were identified by using specifically developed data analysis software.

Diffraction measurements with a boron-based GEM neutron detector

The research of reliable substitutes of 3He detectors is an important task for the affordability of new neutron scattering instrumentation for future spallation sources like the European Spallation Source. GEM (Gas Electron Multiplier)-based detectors represent a valid alternative since they can combine high-rate capability, coverage of up to area and good intrinsic spatial resolution (for this detector class it can be better than 0.5 mm). The first neutron diffraction measurements performed using a borated GEM detector are reported. The detector has an active area of and is equipped with a borated cathode. The GEM detector was read out using the standard ISIS Data Acquisition System. The comparison with measurements performed with standard 3He detectors shows that the broadening of the peaks measured on the diffractogram obtained with the GEM is 20–30% wider than the one obtained by 3He tubes but the active area of the GEM is twice that of 3He tubes. The GEM resolution is improved if half of its active area is considered. The signal-to-background ratio of the GEM is about 1.5 to 2 times lower than that of 3He. This measurement proves that GEM detectors can be used for neutron diffraction measurements and paves the way for their use at future neutron spallation sources.

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.

Combined neutron and laser techniques for technological and compositional investigations of hollow bronze figurines

Here, an innovative non-invasive multi-analytical approach for the archaeometallurgical characterisation of ancient bronze artefacts using high resolution neutron tomography, time of flight neutron diffraction, and laser induced plasma spectroscopy has been investigated. We show its effectiveness through an example application aimed at describing the crafting processes, characterising the alloy compositions and deterioration phenomenologies of three small bronze figurines from the antiquarian collection of the Egyptian Museum of Florence. The present methodology has allowed unprecedented overall archaeometallurgical descriptions of these artefacts based on the detection of fine morphological details, degree of mineralisation, elemental and phase composition of the metal walls, and mineral contents of the core materials. Such an approach can be extended to other hollow copper alloy artefacts in order to identify their raw materials and interpret their technological processes.

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.

A multitask neutron beam line for spallation neutron sources

Here we present a new concept for a time-of-flight neutron scattering instrument allowing for simultaneous application of three different techniques: time-of-flight neutron diffraction, neutron resonance capture analysis and Bragg edge transmission analysis. The instrument can provide average resolution neutron radiography too. The potential of the proposed concept was explored by implementing the necessary equipment on INES (Italian Neutron Experimental Station) at the ISIS spallation neutron source (UK). The results obtained show the effectiveness of the proposed instrument to acquire relevant quantitative information in a non-invasive way on a historical metallurgical sample, namely a Japanese hand guard (tsuba). The aforementioned neutron techniques simultaneously exploited the extended neutron energy range available from 10 meV to 1 keV. This allowed a fully satisfactory characterization of the sample in terms of metal components and their combination in different phases, and forging and assembling methods.

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.

Neutron diffraction characterization of Japanese armour components

In this work we present an extensive time of flight neutron diffraction (ToF-ND) study on some Japanese armour components. The experiments were carried out at the INES diffractometer at ISIS, the pulsed neutron source in the UK. In particular, we have studied seven Japanese helmets (kabuto) made between the 16th and 17th century. By means of this non-invasive approach we have been able to determine quantitatively the phase composition and the microstructural properties of these artefacts. The samples belong to different periods and different levels of quality. The observed differences were quantified in terms of the accuracy and amount of their working. A quantitative determination of their phases and of the thermo-mechanical treatments has been obtained for all investigated samples, confirming that the use of ToF-ND represents one of the most suitable non-destructive approaches for the characterization of metal archaeological artefacts.