Handheld methods in archaeological research on large copper alloy assemblages: HH-XRF against HH-LIBS

Abstract

When alloy composition information is sought across a single large artefact assemblage, how well do handheld methods solve the problem of museum environments which restrict the movement of artefacts and destructive sampling, and which have limited in-house technical resources? The usefulness of relatively low-cost handheld analytical instruments still needs evaluating in such arenas. The potential advantages which handheld laser-induced breakdown spectrometry (HH-LIBS), with its affordability, speed and micro-destructive corrosion-penetrating ability, might offer over handheld X-ray fluorescence (HH-XRF)/portable X-ray fluorescence (pXRF) in large intra-assemblage comparisons of broad copper alloy composition were examined and reported on by the present study (tin and lead being the elements of interest). The context was an archaeological study in a major Greek museum, aimed at exploring the social and economic significance of alloying choice at a single large representative site of the Bronze–Iron transition, c.1200 bc. Archaeological interpretations are presented in another paper, with the alloying patterns/choices identified only being outlined in the present paper. The results of the methods comparison described suggest that HH-LIBS has potential, but that HH-XRF, despite its variable limitations in relation to penetrating corrosion (discussed here), is still the most reliable method for work in such circumstances.