During the last years we started to study the application of ionoluminescence (IL) to identify the provenance of lapis lazuli, a semi-precious stone used since the fifth millennium b.C. to realize precious artefacts. For this purpose, we studied the luminescence properties of the single mineralogical phases and the trace elements therein, that can vary among extracting sites. Ionoluminescence revealed to be very useful for two main reasons:
1) Employed in the “broad-beam mode” it allows to quickly identify the mineralogical phases in the analysed artworks.

An example of measurement: first of all we analyse a large area using the broad-beam luminescence (b), then we switch to the microbeam and we analyse a selected area (in this case diopside, with a yellow luminescence), measuring the luminescence emission spectrum and the composition, included the trace elements.

2) It allows to identify differences in the emission spectra of similar mineralogical phases in lapis lazuli coming from different places.

Luminescence spectra of diopside and wollastonite from different provenances. The luminescence from Pamir samples could present a band centered around 700 nm, not present in samples from the other two Asian provenances.

IBIL: time-resolved response of luminescence induced by pulsed proton beams

The study of the decay time of the luminescence centre at 580 nm, present in all the Asian samples, could lead to identify further markers to discriminate different Asian provenances. Since the decay time depends on the characteristics of the luminescence centre, also influenced by the trace elements not directly involved, we propose to study possible differences in decay time among samples from various provenances. We expected also very long decay times, depending on the orogenetic formation and the concentration of trace elements.

One of the main advantages to perform this study employing ions, instead of other probes, is that the trace elements analysis is simultaneously obtained.

RL: study of the possibility of extending the standard IBIL technique to X-ray sources

The luminescence emission can be induced by different kinds of probe; among the most used there are: electrons in cathodoluminescence (CL) and ions in the ionoluminescence (IL). Both the techniques are not transportable and so are unsuitable to be employed on objects that cannot be moved (as most of the artworks of interest in the Cultural Heritage field).
For this reason, we propose to create a portable instrument to perform luminescence measurements and especially to couple the luminescence spectrum with the elemental one. Since X-Ray Fluorescence is the elemental technique most employed for the material characterisation in the historical/artistic/archaeological fields, X-Ray Luminescence was naturally chosen (luminescence induced by an X-ray beam). This method is already employed in different laboratories to characterise materials, but it never been made portable and so suitable for the analysis of Cultural Heritage materials.