An evaluation of portable X-Ray fluorescence on applied blue faience glazes: A study using replicate glazes of the Late, Ptolemaic and Roman period in Egypt

Wilkins, James 2019. An evaluation of portable X-Ray fluorescence on applied blue faience glazes: A study using replicate glazes of the Late, Ptolemaic and Roman period in Egypt. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

This thesis presents a systematic evaluation of energy dispersive hand-held X-ray fluorescence (HH-XRF) on the semi-quantitative net peak analysis (NPA) of Late, Ptolemaic and Roman Period (644 BC to AD 395) faience from Egypt. The study develops a non-destructive protocol in the analysis of faience glazes using HH-XRF, a relatively recent technological innovation in cultural heritage. The benefits (e.g. portable, non-destructive, non-radiological source (i.e. X-ray tube)) and limitations (e.g. depth of analysis, layered analytes (i.e. glaze on body)) of HH-XRF are examined. Replicated faience glazes were produced as a part of the HH-XRF evaluation. Glaze recipes were derived from the literature involving experimental archaeology and instrumental analysis. One body and three glaze batches were produced that were aesthetically and structurally similar to the archaeological material. The glaze batches were fired on raw and bisque-fired bodies in a raw and prefritted state to produce 30 replicated glaze samples. The HH-XRF parameters (e.g. voltage, current, acquisition time) were evaluated using Corning Glass B as the known analyte. Optimum results were based on a compromise (bivariate coefficient) between high precision (Cv) and high signal-to-noise ratio (SNR). Multivariate statistics were explored providing the optimal methods for data preparation and analysis using hierarchical cluster analysis, principle component analysis and K-means analysis. The HH-XRF (NPA) measurements for high (40 kV) and low (15 kV) voltages combined with multivariate statistics successfully discerned the three replicated faience glaze sets. A small case study of faience glazed sherds from Saqqara were examined and analysed using the optimally determined settings to illustrate HH-XRF use on archaeological material. The results categorized the faience into 5 groupings (with subgroups) based on composition. The project was designed to help field archaeologist and others responsible for the study and care of faience objects by providing steps that can be utilized in the field or in a laboratory setting using materials and tools that are readily accessible. This is especially useful in places like Egypt where there are on-going excavations but exportation of artefacts is difficult to impossible and importation of radiological sources is highly regulated.

Item Type:	Thesis (PhD)
Date Type:	Submission
Status:	Unpublished
Schools:	History, Archaeology and Religion
Uncontrolled Keywords:	X-Ray Fluorescence, pXRF, HH-XRF, Faience, Glazes, Roman, Ptolemaic, Late Period, Egypt, Multivariant Statistics, Principle Component Analysis, Hierarchical Clustering, Dendrogram, K-means Analysis, Replicated Glazes, Scanning Electron Microscope, SEM-EDS, SEM-BSE
Date of First Compliant Deposit:	4 January 2019
Date of Acceptance:	3 January 2019
Last Modified:	26 Mar 2021 16:06
URI:	https://orca.cardiff.ac.uk/id/eprint/118081

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