A new version of a portable polonium source for the non-destructive PIXE (Particle Induced X-ray Emission) analysis in the cultural heritage field

A new version of the portable polonium source, named L-PIXE (large-particle induced X-ray emission), to be used for the non-destructive analysis in the Cultural Heritage field, was realised in the framework of a collaboration between the Italian LNS-INFN (Laboratori Nazionali del Sud-Istituto Nazionale di Fisica Nucleare) and IBAM-CNR (Istituto per i Beni Archeologici e Monumentali-Consiglio Nazionale delle Ricerche). The new source presents a compact geometry and it was designed to operate with large area SDD (silicon drift detector) detectors. In particular, the L-PIXE source was coupled to a 50 mm(2) SDD detector and tested by measuring geochemical reference materials. Results evidenced a gain factor, in terms of counting statistics in the measured X-ray spectra, equal to 11-12 with respect to the previous versions of the source. A preliminary evaluation of the MDL (minimum detection limit) of the new experimental set-up evidenced the possibility of using the new L-PIXE source for identifying the presence of minor and, in some cases, trace elements composing samples under investigation.