The external micro-PIXE (Proton Induced X-ray Emission) facility of the KN3000 Van de Graaff accelerator at the Department of Physics of the University of Florence has been used to analyze individual minerals and groundmass of volcanics from Filicudi (Aeolian Islands).
The studied samples are typical calc-alkaline lavas varying in composition from basalts to basaltic andesites up to HK-andesites.
For PIXE measurements the polished sections of rocks were directly bombarded with 3 MeV proton beams of 50 and 200 µm diameter for phenocrysts and groundmass respectively. In order to optimize sensitivity over the whole range of detectable elements, two Si(Li) detectors were simultaneously used during each irradiation. The obtained X-ray intensities have been used to extract relative concentrations by means of an absolute computing procedure which has to be shown to yield reliable results on geological standards.
The detected abundance of some trace elements in the minerals and in the corresponding groundmass made it possible to obtain estimates of solid/liquid partition coefficients.