SIMPLE METHODS FOR QUANTITATIVE X-RAY-FLUORESCENCE ANALYSIS OF ANCIENT METAL OBJECTS OF ARCHAEOLOGICAL INTEREST

In quantitative EDXRF analysis of ancient metallic objects two main di fficulties arise: i) how to find out the correction factors for the ir regular shape or relief effects and ii) how to measure the true compos ition of the bulk metal under the surface patina. In the case of coins , taken as a typical example, point i) could, in principle, be by-pass ed by casting pure metal copies of specimens and comparing XRF intensi ties with the ones from regularly shaped standards. The interest in ex amining coins, however, mostly depends on the possibility of the analy sis method to be applied to several pieces and XRF analysis should pro ve to be unpractical in this case. In general we have been looking for methods,which are non destructive, simple, cheap, with no consequent effect and possibly apt to in-situ measurements by portable instrument s. Gold alloy objects do not normally present a patina on the surface so, by choosing proper geometric conditions during irradiation and by resorting to XRF line intensity ratios, it is possible to get rid of t he problem of evaluating geometric factors. (C) 1997 by John Wiley & S ons, Ltd.