Analysis of cultural heritage reference materials by portable and energy dispersive X-ray fluorescence measuring methods: results reliability assessment (original) (raw)
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ICOM-CC 17th Triennial Conference Preprints, Melbourne, 15–19 September 2014, 2014
Falling costs, smaller sizes and increasingly user friendly interfaces have led to the wide use of handheld portable x-ray fluorescence instruments (HHpXRF) in the analyses of cultural heritage objects. Methodological considerations on the validity of results derived from HHpXRF have led to debates in conservation and archaeological literature. Relatively little attention has been paid to the applicability of HHpXRF to the characterisation of archaeological copper alloys. This paper evaluates the use of Bruker AXS Tracer III-SD on a range of certified copper alloys which were selected based on their occurrence in antiquity. Alloys were then electrochemically corroded and analysed to examine the impact of corrosion layers on HHpXRF data. Qualitative and quantitative data processing methods are compared and the impact of source to-sample distance on the HHpXRF results is examined. The implications and relevance of data accuracy are discussed with regard to archaeological interpretation and uses in conservation. The tables from this paper can be downloaded as spreadsheets from: https://www.researchgate.net/publication/266564964\_Testing\_the\_applicability\_of\_handheld\_portable\_XRF\_to\_the\_characterisation\_of\_archaeological\_copper\_alloys
X-Ray Spectrometry
Energy dispersive X-ray fluorescence (EDXRF) is widely used in the study of archeological metal artifacts, heritage and art history, where the fragile nature of the objects requires the use of noninvasive techniques such as the EDXRF, which in addition, is fast and very affordable.An EDXRF analysis of copper-based artifacts from Late Bronze Age metal hoards from Central Portugal is presented.The EDXRF measurements were carried out by using an X-ray tube with a Mo anode and a commercial Si-PIN detector. The data acquisition was performed by keeping small distances between the X-ray window, the sample and the detector. Both patinated and polished areas were analyzed: the relative composition of the artifacts was inferred from the fluorescence spectra obtained. Copyright © 2012 John Wiley & Sons, Ltd.
Elemental analysis of ancient ceramics is primarily used in provenance research, where defined compositional groups are attributed to particular raw materials sources or production locations. Requirements in data quality and analytical performance are high, as is the need for clear and reproducible methodologies and the availability of information on the above to ensure interlaboratory comparability and long-term data validity. This paper outlines the measurement parameters of a dedicated calibration setup for the analysis of ancient ceramics using wavelength-dispersive X-ray fluorescence spectrometry. The specimens are prepared as concentrated glass beads, allowing the measurement of 26 elements from a single sample, thus minimising sample size requirements. Certified and non-commercial standards are used to evaluate the performance of the method in terms of detection limits, precision, repeatability and accuracy. The materials used cover a range of compositions in line with the matrix variability encountered in archaeological ceramics. The data confirm the high standard of the method and highlight specific limitations. An initial assessment of comparability with other setups used in ceramic analyses, primarily neutron activation analysis, is given through a discussion of performance on commonly analysed materials. The advantages of the proposed method include excellent analytical performance, analysis of a large suite of elements including all major, minor and a good range of traces, relatively small sample sizes and preparation of samples that can be stored and reanalysed. Copyright
Metalla 24 (2) 81-85, 2018
In this paper I shall explore some of the negative consequences of the current popularity of portable X-ray fluorescence (pXRF) analysis. There is no doubt that this portable device, which can be taken to museums and sites, has revolutionised the study of the compositions of many classes of archaeological material, but the apparent simplicity of its operation and the generation of analytical results has also created problems, particularly as regards the analysis of metals. Many archaeologists and museum curators do not seem to understand that pXRF data generally does not reflect bulk composition of copper-based metalwork. PXRF analyses the surface of an artefact, which is of course subject to weathering and alteration, and, moreover, some elements segregate or enrich on the surface of objects during metallurgical processes. A further problem is that it is becoming more and more common for museum curators to refuse to authorize destructive methods of analysis since pXRF analysis can be effected without damage to ancient artefacts. The misunderstanding by many archaeologists and curators of the nature and significance of pXRF is illustrative of the misunderstandings that exist between materials scientists and archaeologists.
Handheld XRF mapping of elemental composition of Roman silver artefacts: preliminary results.
Archaeometallurgy in Europe IV., 2017
The goal of this study was to measure the chemical composition of late Roman silver artefacts preserved in the Hungarian National Museum by means of systematic handheld X-ray fluo-rescence analysis. The mapping of the elemental composition of silver objects is suitable for revealing their chemical inhomogeneity. The measurements were systematically performed along a pre-designed grid to cover the whole surface of the artefacts. Four plates were analysed in the framework of the Seuso Research Project: Seuso Platter and Geometric Platter from the Seuso Treasure and Ribbon Platter and Rosette Platter from the «Šabac Treasure». All the plates were made from high-quality silver (above 95 wt% Ag) with up to 3 wt% of copper as alloying element. Bismuth shows significant enrichment in the Seuso Platter, compared to the other three, indicating a different ingot and/or different origin of ore used for production. Silver and copper may show a slight concentration variation along the radii of the plates.