Using spiked, fired clay samples for developing robust quantification algorithms for pXRF of pottery

Summary

Meanwhile absolute concentrations rather than relative, instrument and setting specific values are requested as scientific standard in publishing provenancing results. Recent publications suggest that there is no reliable vendor software for elemental quantification of pottery with pXRF. It is unclear whether this is due to a lack of precision in the given trace element values of reference standards, or uncorrected matrix effects, or both. We faced similar problems when using >30 reference standards for quantification by direct comparison of counting rates. To get a better understanding we prepared fired clay samples spiked with Ti, Fe, Ga, Rb, Sr, Y, Zr and Nb. Using different commercial clays we recognized a strong impact by Fe absorption/enhancement, which needs correction if a meaningful comparison of pottery from different production sites is intended. Furthermore we were able to use the concentration range of the spiked samples to improve the deconvolution software provided by the vendor for spectral interference, which we did not even recognize before. To underline the necessity of a diligent calibration of pXRF instruments we present data with and without the established correction algorithms for separating medieval waster assemblages which have partially overlapping trace element patterns, but differ in its Fe content.

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This Resource is Part of the Following Collections

• Society for American Archaeology 80th Annual Meeting, San Francisco, CA (2015)

Keywords

Spatial Coverage