Rimozione laser di biodeteriogeni da manufatti lapidei: definizione dei parametri di irragiamento e valutazione analitica

The periodical removal or impairment of biodeteriogens represents a fundamental need in the preservation of outdoor stone cultural heritage. In the present work, we have investigated the potential of laser treatments of lichens and biofilms from Carrara marble artefacts. Irradiation tests have been carried out on seriously deteriorated marble slabs from the monumental tombs of the English Cemetery of Florence using different wavelengths (532, 1064 and 2940 nm) and pulse durations (10 ns, 40-120 ?s and 400 ?s). The effects of laser tests have been characterized using various analytical techniques (optical and electronical microscopy, colorimetry, etc.). In particular, Chlorophyll Fluorescence with Pulsed Amplitude Modulated (CF-PAM) has allowed quantifying the impairment effects to the outer phototrophic organism residues, while the damage to the endolithic growths has been evaluated by means of stratigraphic analysis using optical microscopy and SEM examinations following osmium tetroxide staining of cytoplasmic lipids.