|Analytical technique description:||
Highly chemically specific laser spectroscopy technique able to provide information on the molecular composition of the materials. In the field of conservation of Cultural Heritage it is widely employed for the analysis of gems, pigments and colorants, as well as for the study of the distribution of organic and inorganic conservation products inside the materials.
Both massive and cross sections of the samples can be analysed with a spatial resolution of a few µm (micro-Raman). The benchtop instrument is also equipped with a motorized stage for mapping and with optical fibres probes enabling the laboratory analysis of large objects.
In situ non destructive analyses of the surfaces are carried out with the portable instrument. The data could be affected by the fluorescence radiation that could hide the Raman signal.
When the laser source impinges on a substance the sample scatters light. A component of the light is strongly elastically scattered (Rayleigh radiation); an additional component is anelastically scattered (Raman scattering), with a frequency that depends on the normal mode frequencies of the molecule of the sample. It is thus possible to derive information on the molecular composition of a given substance.
Senterra dispersive Micro-Raman spectrometer (Bruker) equipped with two exciting lines (785nm and 532 nm) (Milan Unit).
-Portable Raman Xantus-2TM (Rigaku) equipped with two exciting lines (1064 nm and 785 nm) (Milan Unit).