Combined PIXE/PIGE and IBIL with external beam applied to the analysis of Merovingian glass beads

New improvements on our archaeometry line at the cyclotron of the Institute of Nuclear and Atomic Physics and of Spectrometry of the University of Liege have allowed the use of PIXE/PIGE and IBIL in-air for the analysis of cultural heritage objects. The extraction is performed through a 100 nm thick Si3N4 window. The detection set-up consists now of two X-ray and one γ-ray detectors, together with a fiber optic UV-visible spectrometer. This set-up has already been tested for the analysis of modern corundum and is now adapted to the analysis of archaeological artefacts. In this work, we have used it to analyse 216 out of the 5000 Merovingian glass beads that come from the necropolis of Bossut-Gottechain (Belgium), one of the most important ever found in Belgium. The IBA analyses confirmed the typological division of different beads groups through chemical composition that gives us new insights on fabrication techniques of glass matrices and colorants.