Laser-Based Spectroscopic Systems to Investigate Marble Busts in the Chigi Palace of Ariccia

The application of laser-based spectroscopic systems in the field of cultural heritage is now well established. In particular, LIF (Laser-Induced Fluorescence)-based instruments present some features that make them particularly valid in the field of cultural heritage, where the respect and the conservation of the target must be maximum. In fact, they have the ability to work in situ at several meters of distance from the target, they are non-destructive, don't require sampling and can be portable while providing first results in real time. The technique’s effectiveness as a diagnostic tool for cultural heritage materials, like paintings, wood and stone, has been demonstrated widely. As part of the ADAMO project, three marble busts, preserved in the Chigi Palace of Ariccia, attributed to the Bernini school have been analysed by LIF to obtain information on constituent materials and on previous restoration processes, not available in this case. Two different LIF systems developed by ENEA have been used, to reduce the time for measurements and to limit the number of measurement points. Data post-processing has highlighted areas with treatments completely invisible to the naked eye as well as some differences on the surfaces of the various busts. Moreover, Raman measurements have been carried out in situ on the same busts by using a high-performance laboratory Raman system coupled with optical fiber head confirming the LIF results on the investigated samples.