The fundamental properties of ice have always attracted a lot of interest due to omnipresence of ice in many different natural contexts. Since cubic ice recently become experimentally accessible from a low-density gas hydrate precursor [1, 2], it has been possible to measure its density as a function of temperature in the whole thermodynamic range of metastability. We found strong analogies with respect to the other ice I polytype, i.e., hexagonal ice Ih [3], including the presence of a negative thermal expansion behavior at low temperature. Based on these results, a new enthalpy calculation quantifies the metastable nature of the cubic form and, consequently its inaccessibility from a "normal" ice Ih precursor.

Little is known about the life of the Florentine artist Attavante degli Attavanti (1482–1525), and even less about the materiality of his illuminations. For the first time, a manuscript and an early printed book were analysed to gain new insights into his painting techniques and materials. To preserve the integrity of these valuable and fragile objects, a non‑invasive methodology including spectroscopic techniques (macro‑XRF (MA‑XRF), fibre‑optic reflectance spectroscopy (FORS), Raman spectroscopy) and extensive microscopy, enabled the identification of a wide range of pigments and metals. The two volumes were compared in terms of palette and painting techniques, with particular attention to the execution of flesh tones, landscapes, and the modelling of draperies. Many similarities and a few differences emerged. This study provides the first insights into Attavante’s material practice and helps refine our knowledge of his technique and how much his style has actually changed over time.

Bragg edge neutron transmission analysis is a non-destructive technique that can be used for the investigation of properties of crystalline solids, such as microstructure, texture, strain or defects. In this work, Bragg edge imaging is applied to characterize additively manufactured metal samples produced via powder bed fusion-laser-based, featuring an innovative star-shaped geometry. This process can induce microstructural inhomogeneities within the material, thereby compromising the mechanical integrity of the final component. For this reason, a comprehensive understanding of the manufacturing process is essential to identify optimal operational parameters. Because of the lack of non-invasive techniques allowing an in-depth study of the microstructure of these samples, Bragg edge imaging is applied for providing detailed quantitative information on the manufacturing process. In this context, the final aim of this work is to investigate how the production process influences the final manufactured components. To study these effects, three different additively manufactured samples made of different metal alloys have been characterized by Bragg edge analysis. Characterization of elastic lattice strain, density of crystallographic defects and texture reveals significant discrepancies between the samples and their respective starting powders. These findings elucidate the various effects induced by the manufacturing process, which alters the crystalline structure of the metal and introduces anisotropy, potentially leading to mechanical failure of the components.

Gildings, patinas and alteration crusts are common features of many heritage artefacts, especially for metals. Their size depends on many factors, like the manufacturing method for gildings or the conservation state for alteration crusts: in some cases, it can be in the scale of the tens of microns. Such thickness would be difficult to investigate with classical non-destructive methods and would prevent getting information from the bulk of the sample. This work proposes an innovative approach for the study of multi-layered materials with the Muonic atom X-ray Emission Spectroscopy technique (μ-XES). Based on the detection of the high-energy X-rays emitted after the muon capture by the atom, this method is characterised by a remarkable penetration depth (from microns to cm). From the surface to the bulk, this technique can evaluate the variation of the elemental composition as a function of depth. The paper focuses on providing an improved interpretation of μ-XES data by coupling the analysis with the use of two Monte Carlo simulation software, GEANT4/ARBY and SRIM/TRIM. With these two software, it is possible to replicate the negative muon experiments and compare the experimental and simulated outputs to address the size of a given layer. To validate this approach, a set of standard gilded bronze and brass foils were measured at the ISIS Neutron and Muon source. From simulations, it was possible to evaluate the thickness of the superficial gold layer, with results in agreement with the preliminary SEM characterisation of the samples.

During the Kofun period (mid-3rd through early 7th century AD) of Japan, earthen mounded tombs were equipped with various burial goods, including numerous iron weapons and tools. While such iron artifacts are sometimes well-preserved, many of them are recovered as heavily mineralized fragments. In these samples it is difficult to derive useful information concerning their original morphology and chemical composition. To acquire meaningful insights into the technological capabilities and manufacturing practices of specific historical periods and regions, archaeometallurgical research must be grounded in the comprehensive statistical analysis of a substantial number of artifacts. It is therefore important to conduct analysis of as many artifacts as possible. Concerning iron sword blade fragments from Kofun-period mounded tombs, it is often the case that almost no metal survives, then it is usually impossible to obtain detailed compositional or microstructural information. It is nevertheless possible to obtain morphological details provided a technique exists to visualize and spatially map the contrast between the iron-rich minerals derived from the blade corrosion and the surrounding non-metal areas. We performed a test experiment to verify the potential of Neutron Tomography to provide such a contrast within heavily mineralized Kofun-period iron sword fragments from Okayama Prefecture, Japan, with excellent results. Moreover, the combination with Neutron Diffraction and X-ray-based techniques has successfully advanced our interpretation of these archaeological finds in a completely non-invasive way.

In this paper, the imaging capabilities and performance of the new neutron imaging beamline developed at the LENA facility of Pavia (Italy) in the framework of the NICHE project (Neutron Imaging in Cultural HEritage) are presented. For this purpose, the estimation of bronze and brass alloys attenuation coefficient has been obtained through imaging analysis of a set of Cu-based alloy reference samples produced ad-hoc with chemical composition similar to ancient artefacts. In addition, some samples were realised using a different cooling ramp in order to test the influence of the alloy production procedures in neutron attenuation. Moreover, the tomographic capabilities of the beamline were tested for different metallic and plastic materials.

The evolution of metallurgy is a fundamental aspect related to the knowledge of the technological level of ancient civilizations, for which the information was mostly part of an oral tradition. The ancient, preserved artefacts are the only keepers of this long gone knowledge. Most advanced non-invasive techniques provide us the key to access it. Neutron techniques are nowadays the only available approach for revealing, non-destructively and with good spatial resolution, the morphological and microstructural properties within the whole volume of densely composed artefacts such as bronze statues. Application of neutron methods allows us to learn about ancient artefact manufacturing methods and to study at a very detailed level the current conservation status in their different parts. As part of a research project dedicated to the study of ancient Asian bronzes led by the Rijksmuseum Metal Conservation Department, four statues from the Rijksmuseum Asian collection were analysed using non-invasive neutron techniques. In this work, we present the investigation of a South Indian bronze statuette depicting Shiva in the form of Chandrasekhara (AK-MAK-1291, c. 1000–1200 A.D.) by means of white beam tomography, energy-selective neutron imaging (performed on CONRAD-2 at HZB, DE, and on FISH at TU-Delft, NL), and neutron diffraction (on ENGIN-X at ISIS, UK). The application of neutron imaging revealed the inner structure of the statue and allowed us to investigate the conservation state and potential cracking on the surface and in the bulk, to understand the interconnection of the different sections of the statue, and to obtain clues about the manufacturing processes. These morphological and microstructural results were employed to guide neutron diffraction analyses that allowed us to precisely characterize compositional differences, the presence of dendrites and columnar growth peak structures related to casting. This work is a complete non-invasive analytical investigation on an archaeological bronze artefact, providing outstanding results: from a quantitative analysis of the composition and microstructure to an in-depth morphological analysis capable of unveiling details on the ancient casting methods of the statue.

This paper reports on the instrumentation and expertise developed within the INFN-CHNet network for X-ray and neutron imaging, which enable non-invasive identification of materials and production processes in the field of cultural heritage. INFN-CHNet is the network of the Italian National Institute of Nuclear Physics specifically dedicated to the development and application of scientific methods and technologies to cultural heritage. This article focuses on portable MA-XRF scanners, often complemented by additional techniques, PIXE imaging on a newly developed portable accelerator, X-ray radiography and tomography, exploited to their full potential also through the use of portable systems, and neutron radiography and tomography, which require large-scale facilities. In many respects, the information obtained from X-ray and neutron-based methods is complementary, facilitating a comprehensive characterisation of materials, structures, and manufacturing techniques.

The Nuragic civilization (Sardinia, Italy, XVIII-VIII Cen. B.C) developed a flourishing bronze metallurgy. The production of Nuragic bronze figurines from Sardinia represents a rich historical archive that provides key information about the iconography, the metal production and casting techniques, and on the development of metallurgy in the Mediterranean basin. Since the question about their manufacturing method remains without definitive answer, the understanding of the Sardinian bronze metallurgy is essential to determine which manufacturing techniques were employed to produce complex bronze artefacts. In the frame of a wider research project relating to Nuragic bronzes, four artefacts, three anthropomorphic statuettes (a warrior, a priestess, and an offering figure), and one miniature of a basket, were made available by Museo Nazionale Preistorico "L. Pigorini" (Roma, IT). In this work we present the results of the analyses conducted on a bronze figurine depicting an iconic type of Nuragic figure: the Priestess. The analysis was performed using White Beam Neutron Tomography (NT) and Bragg Edge Neutron Transmission (BENT) at the Paul Scherrer Institut (PSI) (Villigen, CH). Neutron techniques are nowadays the only available approach for revealing, non-destructively and with good spatial resolution, the morphological and microstructural properties within the whole volume of solid cast metallic artefacts such as this bronze statuette. This work presents the result of a non-invasive analytical investigation on an archaeological bronze artefact, providing outstanding results: from a quantitative analysis of the composition to an in-depth morphological and microstructural analysis capable of unveiling details on the ancient casting methods of the statuette.

The manufacturing and corrosion properties of metal artefacts are significant for archaeologists and conservators. In this study, non-destructive neutron-based techniques are applied on ancient copper-iron arrows. The archaeological samples were excavated from a Western Han tomb (202 BC - AD 8) near the Han Chang’an city site (the capital of Western Han dynasty) in China. This is the first time that the combination of neutron resonance capture analysis, neutron diffraction, neutron tomography, and Raman spectroscopy has been used in Chinese cultural heritage to obtain useful information about the arrows. The results indicate that one arrowhead is made of low-Sn, high-Pb bronze, while the other is composed of high-Sn, low-Pb bronze. These analyses also reveal the production method of these arrows, with the iron tangs likely being cast first and then connected to bronze arrowheads through casting. Furthermore, due to the variations in materials used, certain parts of the arrows were more susceptible to corrosion than others; specifically, those made of pure iron were more prone to corrosion than their bronze counterparts. Additionally, it is confirmed that the iron inside the arrowhead corroded less than the visible iron tang at its base. The corrosion products include cuprite, goethite, hematite, magnetite, cerussite, azurite, malachite and lepidocrocite. These findings are highly beneficial for understanding the making techniques, as well as conservation state and corrosion products associated with archaeological arrows.

The iron sword and knife industry was highly developed during the Han dynasties in Chinese history. However, there is not much clarity regarding its presence in the capital. In this paper, we analyzed fragments of seven iron swords and three iron knives excavated in Xi’an city (the capital of Han dynasties) using non-destructive neutron techniques of neutron resonance capture analysis (NRCA) and neutron diffraction (ND) for the first time in China. The results indicate that the hand guards were cast from Cu-Sn-Pb-As alloys, while one knife’s scabbard was made of pure copper. Furthermore, we obtained quantitative results for carbon content, micro-strain and texture effect in different regions of each sword or knife for the first time. This suggests that these iron blades are hypoeutectoid steel, and likely underwent intentional processing such as carburization, decarburizaition and hammering. These findings contribute to a better understanding of the archaeometallurgy related to Han iron swords and knives, which supplements the results obtained from traditional experimental methods. Additionally, it is also significant for further application of neutron techniques in China’s cultural heritage.

This study presents a significant development in the Energy-Resolved Neutron Imaging System RADEN, in the Japan Proton Accelerator Research Complex, Japan. Through a systematic study, the collimation power of the facility was reevaluated. What was initially considered to be values of 230, 420, and 760 have been proven to be much higher. To perform the calculation of the L/D factor of the beam, a state-of-the-art method has been used, along with a standard reference sample to measure the resolution of neutron images. To add robustness to the results, the study compares five different scintillators of different composition and thickness [6LiF:ZnS(Ag) of 50, 100, 200, and 300 μm and Gd2O2S of 50 μm]. The calculated collimating power of the beam ranges between 470 and 1520. These results place a spotlight on an existing discrepancy between the geometrically calculated L/D and the actual measurable quantity, as well as highlight the superior performance of the RADEN beamline.

The Hebrew Scroll, catalogued as Magliabekian Manuscript III 43 and belonging to the National Central Library of Florence (BNCF), is a membranous richly decorated scroll, with colorful depictions of sacred sites through the Holy Land to Lebanon along with handwritten texts in Hebrew and notes in Italian. Despite the fact that the manuscript was originally catalogued as an “object of no artistic or scientific value”, recent paleographic studies dated it to the XIV century and highlighted it as the oldest scroll still available, depicting holy places from Egypt to Lebanon. Nevertheless, precise dating, authorship, and the interpretation of its original function are still uncertain. A suite of complementary techniques was used, including photographic documentation in visible (VIS) light in diffuse light, grazing light, and transillumination, luminescence induced by ultraviolet (UV) radiation, imaging spectroscopy (IS), Macro Area X-ray Fluorescence (MA-XRF), and spot analyses such as fiber-optic reflectance spectroscopy (FORS) in the UV, VIS, and near-infrared (NIR) regions, Fourier transform infrared spectroscopy (FT-IR) in external reflectance mode (ER), and micro-Raman spectroscopy. The results of the non-invasive diagnostic campaign enabled the identification of several constituting materials (parchment, pigments, binder, and inks). The identified materials were consistent with the proposed dating and geographical manufacturing area of the artefact.

Amongst Additive Manufacturing (AM) processes, Powder Bed Fusion (PBF) technologies represent one of the most promising production methods for polymers and metals, and the laser-based systems are certainly the technology that currently guarantee the production of metal parts with complex geometries, shapes, and mechanical properties comparable to those of parts produced using traditional methods. A functionally graded material (FGM) or a multi-material (MM) component can be advantageously produced with several processes and laser-powder bed fusion (L-PBF) is one of the metal-based process for their production and design. In this scenario, the paper proposes a procedure to manufacture FGM or MM parts with standard L-PBF machines, that is equipped with only one powder deposition system, using the 2D multi-material approach, where the material transition occurs between the layers with a material change along the building direction. Joints between materials of common interest, such as AISI 316L CuCrZr alloy, AISI 316L 16MnCr5 steel, and Al-Sc AlSi10Mg alloy, were considered. The joints were analysed by means of metallographic investigation, neutron tomography (NT) analysis and tensile tests. The results of metallographic and tomography analyses highlight the continuity of joints establishing the possibility and the effectiveness to manufacture FGM or MM. Also, the tensile tests showed interesting results, demonstrating that the mechanical properties of the joint depend on the bulk alloy properties and on the internal structural integrity.

This communication presents the results obtained at an experimental campaign at PSI BOA beamline using the combination of the ANET Compact Neutron Collimator (CNC) with the actual BOA pin-hole system. Through extensive resolution campaigns, it has been possible to quantify and understand the effects of improvement on the beam divergence when combining the two collimating systems. A new theoretical approach to this problem is described and discussed. The effect is expected not to be limited to the specific case that has been studied at PSI BOA but to have a more general validity for neutron collimation systems.

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.

Muonic atom X-ray Emission Spectroscopy (mu XES) is a novel technique in the broad field of non-destructive methods for cultural heritage analysis. It relies on the interaction of a probe of negative muons with matter and following emission of X-ray radiation. Since the muon mass is about 207 times bigger than the electron, these emitted X-rays are highly energetic and are characteristic of the emitting atom, making it possible to cover a wide part of the periodic table (from lithium to uranium). The multi-elemental range, a negligible self-absorption of the X-rays and very low residual activity left in the sample after irradiation make mu XES a very powerful probe for material characterization. In addition, by coupling the data analysis with Monte Carlo simulation methods, it is possible to asses the depth of the layers that are present in a given sample. In this work, preliminary results of the analysis on two gilded surfaces are reported.

In this work, achieved results on the NICHE project (Neutron Imaging in Cultural HEritage) are presented. It fits in the frame of the Cultural Heritage Network (CHNet) of the Italian Nuclear Physics Institute (INFN), and is devoted to the development and usage of a new neutron imaging station on the thermal port of the 250 kW TRIGA Mark-II reactor installed in the Laboratorio Energia Nucleare Applicata (LENA) in Pavia (Italy). The application of neutron radiography to the diagnostic in the cultural heritage field is quite widespread among the research community since it is a non-invasive technique which allows for revealing of the inner structure of the investigated objects, the identification of different materials and their relative spatial distribution with a suitable level of resolution and contrast. We present here the status and progresses within the project: technical characteristics of the beamline and the imaging station component, measuring configuration, possible applications, and examples.

In this paper, NICHE (Neutron Imaging for Cultural HEritage), the new neutron imaging facility of the Italian National Institute of Nuclear Physics (INFN) is shortly presented. We report on the main features of the beamline, the specifications of the detection set-up, and the performances of the imaging system. NICHE is installed at the TRIGA reactor of LENA (Laboratorio Energia Nucleare Applicata) Pavia University laboratory (Italy). The imaging facility was designed during 2020, installed in the spring 2021, and has been in operation since May 2021. NICHE is the first Italian neutron imaging station open to national external users through the INFN-CHNet network application system. NICHE allows users to obtain neutron radiographies and tomographies, thus allowing for morphological characterisation of samples. First results to highlight the potential of the facility are reported. In particular, we show the first results about spatial resolution measurement and 3D reconstruction to provide morphological analysis capabilities.