Faculty of Physics - University of Bucharest

UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

Guest
2024-11-22 2:22

HOME CONFERENCES SEARCH LOGIN NEW USER IMAGES

Conference: Bucharest University Faculty of Physics 2004 Meeting

Section: Optics, Spectroscopy, Plasma and Lasers

Title:

In-situ LIBS Technique on Cultural Heritage

Authors:

J. Striber1 F. Colao, R. Fantoni, V. Lazic, V. Spizzichino2

Affiliation:

1National Institute of Research and Development for Optoelectronics

Centre for Restoration by Optoelectronic Techniques

Bucharest – Romania

2 ENEA, FIS-LAS, C.R. Frascati, V. E. Fermi 45, Frascati (RM), Rome, Italy

E-mail

Keywords:

Abstract:

LIBS (Laser Induced Breakdown. Spectroscopy) technique is very suitable diagnostic technique on cultural heritage: it is possible to effectuate with this measurements in situ, it is a quick technique, it does not need sample preparation, it needs only a small sample quantity, the analysis are effectuated on all the elements together, results are good for different materials and finally, this technique is micro-destructive. The LIBS technique is based upon the analysis of the atomic emission lines generated close to the surface sample. The emission is observed once a laser pulse is focused on the surface, where the very high field intensity initiates an avalanche ionization of the sample elements, giving rise to the so-called breakdown effect. Spectral and time-resolved analyses of this emission are suitable to identify atomic or ionic species originally present at the sample surface. In the present work, we report on the analyses on different kinds of artworks: roman glasses, ancient silver coin, gilded silver textile, archeological metal, prehistoric adobe, marbles and painted ceramics. Parameters we changed are: laser wavelength (1064 nm and 355 nm), energy, pulses number, repetition rate of the laser pulses. For analysis we used the two LIBS methods: acquisition of whole LIBS spectra from 240 nm to 600 nm and stratigraphy. Interesting results were obtained on painted ceramics: even though the pigment penetrated the ceramic we can observe some differences on the spectra, between ceramics and very thin layer of painted. We obtained other one result on archeological metal with stratigraphy. (This results we indicated the discreet presence of crust on the surface). In conclusions, we verified that LIBS is very versatile technique, with witch we obtained qualitative results in situ. On pigment and thin layers we obtained better results using laser at 355 nm. At 1064 nm threshold LIBS was higher than the 355 nm one.