Spatially Resolved Resonant-Raman Scattering Spectroscopy

JUAN JOSÉ LEANI; H.J. SÁNCHEZ; C.A. PEREZ

Campinas

Congreso; Annual User?s Reunion (RAU) of the Luz Synchrotron National Laboratory (LNLS) 2011; 2011

Laboratorio Nacional de Luz Sincrotron

When atoms are irradiated by X ray photons di®erent kinds of interactions take place: the photon can be absorbed by the photoelectric e®ect or can su®er a Rayleigh or Compton scattering. However, under resonant conditions, other low probability interactions can occur. One of these interactions is the resonant Ra- man scattering (RRS). The X ray resonant Raman scattering is an inelastic scat- tering process which presents fundamental di®erences compared to other scattering interactions between X rays and atoms; when the energy of the incident photon ap- proaches from below to the absorption edge of the target element, a strong resonant behavior takes place contributing to the attenuation of X rays in matter. It is well known that the use of synchrotron radiation in trace analysis by x-ray °uorescence (SRXRF) allows to reduce detection limits and to improve sensitivities. The intrinsic characteristics of synchrotron radiation (high intensity, polarization, natural collimation, etc.) and the construction of dedicated sources of synchrotron light make possible to improve detection limits for trace elements in several orders of magnitude. The special characteristics of SRXRF combined with the structural information of RRS provide a unique opportunity of analysing oxidation state in several types of samples with spatial resolution. A special type of application is the analysis of biological samples, which includes surveys related to the human body. In particular the study of dental mineralized tissues. In this work we present preliminary results of micro-RRS analysis with spatial resolution of dental tissues. Linear scannings were carried out covering di®erent areas of a dental sample including dental calculus, i.e., root, dentine, enamel, and tartar. The experimental data required a complex and deep analysis. The prelimi- nary results show clear variations of the RRS structures according to the position of irradiation opening the possibility of a precise structural analysis via Raman scattering combined with micro-XRF.