TY - JOUR A1 - Radtke, Martin A1 - Buzanich, Günter A1 - de Oliveira Guilherme Buzanich, Ana A1 - Reinholz, Uwe A1 - Riesemeier, Heinrich A1 - Scharf, O. A1 - Scholz, Philipp A1 - Guerra, M.F. T1 - Double Dispersive X-Ray Fluorescence (D2XRF) based on an Energy Dispersive pnCCD detector for the detection of platinum in gold N2 - With the aim of improving limits of detection (LOD) of trace elements in a matrix with adjacent fluorescence energies, a simple double dispersive X-ray fluorescence detection system (D2XRF) was constructed to operate at the beamlines BAMline and the mySpot @ BESSY II. This system is based on the combination of a crystal analyzer with an energy resolving single photon counting pnCCD. Without further collimators, the efficient suppression of the background by the pnCCD and the good energy resolution of the crystal results in improved LOD. In first order reflections, an energy resolution of 13 eV for Cu Kα was reached, and an energy range of 1 keV was covered in one shot. This new system was applied to the detection of platinum (Pt) in gold leaves with a LOD of 0.9 mg/kg, which is the lowest attained by totally non-destructive methods nowadays. The presence of Pt in gilded objects from Abydos and Byzantine mosaics provides vital information, as it indicates the alluvial origin of the gold for these examples. KW - Platinum Wavelength dispersive D2XRF KW - Gold Synchrotron XRF PY - 2016 DO - https://doi.org/10.1016/j.microc.2015.10.039 VL - 125 SP - 56 EP - 61 PB - Elsevier Science CY - Amsterdam AN - OPUS4-35777 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Guerra, M.F. A1 - Neri, E. A1 - Radtke, Martin T1 - Gold leaf tesserae: tracing the origins of gold using synchrotron-based techniques N2 - To gain insight into the possible origin of the gold used in the production of tesserae containing gold leaf less than 0.5 μm thick placed between two layers of glass, we propose a non-destructive synchrotron radiation (SR) XRF protocol based on sequential analysis under optimised analytical conditions. Using this protocol, trace element analysis is achieved with detection limits of 1–6 mg/kg. As Pt and Au have adjacent fluorescence energies, we tested the most challenging situation, when Pt is present in very low concentrations in gold. Data obtained by double-dispersive XRF (D2XRF) and μXRF for fourth–ninth-century mosaics decorating nine Eastern and Western religious buildings show that the Eastern and Western tesserae are made from different alloys. However, these alloys are identical to those used to make gold leaf for gilding, because plastic deformation requires the use of gold alloys with high ductility and malleability. Although trace element composition of gold used in the concerned period is only available for coins, by comparing the amounts of Pt contained in the tesserae and in the coins we show that Roman tesserae are made from Roman gold, as described in the documentary sources. We observe for the Byzantine period the use of a Byzantine gold and of gold supposedly from different stages of recycling, and we suggest the use of Umayyad and Abbasid gold for the production of Islamic tesserae. KW - Gold KW - XRF KW - Synchrotron KW - BAMline KW - D2XRF KW - Tesserae PY - 2023 DO - https://doi.org/10.1140/epjp/s13360-022-03638-y SN - 2190-5444 VL - 138 IS - 2 SP - 1 EP - 15 AN - OPUS4-57208 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -