Boglárka Maróti

Non-destructive analyses of bronze artefacts from Bronze Age Hungary using neutron-based methods

In this paper we present the application of various neutron-based methods carried out at the Budapest Neutron Centre. Non-destructive and non-invasive neutron radiography (NR), prompt gamma activation analysis (PGAA) and time-of-flight neutron diffraction (TOF-ND) analysis were applied to reveal more information on raw material and production techniques of bronze artefacts that can be dated to the Central European Bronze Age (2000–1200 BC).

The use of neutron analysis techniques for detecting the concentration and distribution of chloride ions in archaeological iron

Chloride (Cl) ions diffuse into iron objects during burial and drive corrosion after excavation. Located under corrosion layers, Cl is inaccessible to many analytical techniques. Neutron analysis offers non-destructive avenues for determining Cl content and distribution in objects. A pilot study used prompt gamma activation analysis (PGAA) and prompt gamma activation imaging (PGAI) to analyse the bulk concentration and longitudinal distribution of Cl in archaeological iron objects. This correlated with the object corrosion rate measured by oxygen consumption, and compared well with Cl measurement using a specific ion meter. High-Cl areas were linked with visible damage to the corrosion layers and attack of the iron core. Neutron techniques have significant advantages in the analysis of archaeological metals, including penetration depth and low detection limits.

Non-invasive PGAA, PIXE and ToF-ND analyses on Hungarian Bronze Age defensive armour

Non-invasive, archaeometric analyses on selected Hungarian Bronze Age defensive armour is presented here: three greaves, three helmets two shields as well as one vessel fragment were analysed with PIXE, PGAA and TOF-ND. The detected alloy elemental and phase composition as well as its intergranular or spatial concentration distribution reveals important insights into the alloys used and the manufacturing techniques applied c. 1200–950 BC, and allows to reconstruct the production techniques used during the Late Bronze Age.

Characterization of a South-Levantine bronze sculpture using position-sensitive prompt gamma activation analysis and neutron imaging

Complementary neutron-based elemental analytical and imaging methods, i.e. position sensitive prompt gamma activation analysis and neutron tomography, were used on a bronze sculpture group of suspected South-Levantine origin. Based on the radiography and tomography images, individual figurines were chosen for elemental analysis. Selected parts were analyzed, and the bronze alloy parts were found to contain 14 mass-percent tin and 84 mass-percent copper. The non-bronze pieces contain Fe, Cl, H, Pb, S, Mn and several minor and trace constituents. This study demonstrates the synergy of the visual and compositional data when drawing conclusions about such valuable and complex metallic artifacts.

Comparison of low-energy and coaxial HPGe detectors for prompt gamma activation analysis of metallic samples

In the prompt-gamma activation analysis, the spectra of multi-element metallic samples contain low-energy regions with complicated multiplets that are difficult to evaluate by fitting. This has an impact on the accuracy and precision of the final results. To overcome this, parallel measurements with Compton-suppressed coaxial HPGe and high-resolution, low-energy germanium detectors, with and without Compton-suppression, were completed in order to assess the performances of the setups under controlled conditions. The selectivities, the signal-to-background ratios and other characteristic features of the setups are compared, and the results are discussed.

Benchmarking PGAA, in-beam NAA, reactor-NAA and handheld XRF spectrometry for the element analysis of archeological bronzes

Novel detection strategies were developed to improve the PGAA methodology in the analysis of bronze and brass objects. Instrumental neutron activation analysis and X-ray fluorescence were also involved in this study for comparison. The approach was tested on a set of IRMM-certified copper alloys. Reference values for the concentrations of four major additive components (As, Zn, Sn, and Pb) were compared with the results obtained by the involved methods. The bias observed between the reference Sn values and the initial PGAA results was successfully addressed by considering the interference of this line with low intensity copper prompt gamma peaks. In this report results are presented, and the analytical merits are compared.

Compositional studies of functional orthodontic archwires using prompt-gamma activation analysis at a pulsed neutron source

Prompt-gamma activation analysis (PGAA) measurements were carried out at the ISIS Spallation Neutron Source on two sets of functional commercial stainless steel orthodontic archwires, aiming at providing insights into the elemental and isotopic composition differences of two nominally equivalent archwires. The results were compared to those obtained from parallel cold neutron PGAA measurements on the same samples at the Budapest Neutron Centre in order to test the current status of PGAA at a pulsed neutron source and eventually to inform improvement in set-up and acquisition methods. In addition, time-resolved PGAA (T-PGAA) that combines PGAA and neutron time-of-flight methods was applied to the present set of samples, allowing the measurement of the neutron energy dependence of the PGAA spectra. The advantages of this technique were demonstrated to be that through incident neutron energy selection, spanning 0.07–67.94 eV, enhancement or decrease of specific gamma lines associated with isotopes of interest could be achieved. These were shown to reduce peak interference and to increase the signal-to-background ratio for certain species in order to facilitate accurate elemental identification. Suggestions for potential performance improvement for this evolving technique are proposed.

X-ray and neutron-based non-invasive analysis of prehistoric stone artefacts: a contribution to understand mobility and interaction networks

Carbonate-rich archaeological artefacts are difficult to identify and correlate between them and with raw materials of such heterogeneous geological sources, especially when only non-invasive analysis is possible. A novel combination of X-ray and neutron-based non-invasive analysis is implemented and used for the first time to study prehistoric stone idols and vessels, contributing to culture identity, mobility and interaction in the recent Prehistory of Southern Iberia. Elemental composition was obtained by prompt gamma activation analysis (PGAA) and external beam particle-induced x-ray emission (PIXE); homogeneity of the stone artefacts and the presence/absence of internal fractures were obtained by neutron radiography (NR). These atomic and nuclear techniques, simultaneously used for complementary chemical information, have been demonstrated to be of great value as they provide non-destructive compositional information avoiding sample preparation, crucial in so singular and rare objects. The obtained results, especially of PGAA, are very promising and useful in general assessments of provenance. The stone artefacts show signs of both nearby and long-distance procurement, as well as of unknown attribution.

Neutron based archaeometallurgical investigation of Picenan and Roman age metal objects from the Academia Georgica Treiensis collection (Italy)

ABSTRACT Non-destructive prompt gamma activation analysis (PGAA), neutron radiography (NR) and high resolution time-of-flight neutron diffraction (TOF-ND) have been applied to investigate metal archaeological artefacts belonging to the Academia Georgica Treiensis (AGT) collection. 8 archaeological items have been analysed, by using the facilities of the Budapest Neutron Centre (BNC). Some of these objects mostly dating back probably to the VI-IV century B.C. and presumed to be discovered in the Marche Region, Italy. The primary goal of the analyses was to advance the correct technological and material description of the objects, providing scientific data for further and more comprehensive comparative analyses also covering the find material from the close archaeological sites. The neutron investigations allowed determining the bulk composition, also providing either a qualitative and quantitative assessment of the phase composition and the structural properties of the constituents, or radiographic images, which would finally help to identify possible manufacturing techniques. Additional examinations, carried out by external milli-beam particle induced X-ray emission spectroscopy (PIXE), provided quantitative analyses of major and trace elements (e.g., Fe, Pb and As) in order to recognize the constitutive alloys and to supply information on the near-surface elemental composition, complementary to the data characteristic for the bulk. The obtained results, thought to be useful to set up a classification according to the chemical composition, and this way allow achieving important information related to the possible provenance of the objects.

The bottom of the looted cauldron. Part I.

The following study deals with a looted metal sheet artefact probably originating from the Balkan region. Our main goal is to give a preliminary technological characterization of the object by the aid of four different analytical methods (macro- and microscopic observations, Neutron and X-ray Radiography, X-ray Fluorescence Spectroscopy). Using these different techniques together allowed us to characterize this complex metal sheet object more precisely than it would have been possible by traditional archaeological methods. According to our results, it seems that the technological characters of the artefact (e.g. the manufacturing technology, decorations, repair marks) are very similar to the metal sheet cauldrons of the Late Bronze Age and Early Iron Age.