BONGIOVANNI guillermina Azucena
congresos y reuniones científicas
Currently Research Activities in Environmental and Surface Science using µ-XRF and Grazing-exit XRF Spectroscopy at the XRF beamline of the LNLS
PEREZ, CARLOS A; SANCHEZ, HÉCTOR.; MOREIRA, SILVANA; BONGIOVANNI, GUILLERMINA; PEREZ, ROBERTO D; RUBIO, MARCELO
Conferencia; EXRS 2006 (European Conference on X ray Spectrometry); 2006
LNHB-CEA LIST & ENS Lion (www.nucleide.org/exrs2006)
Micro X-ray fluorescence analysis using synchrotron radiation has proved to be a very powerful analytical technique for trace elements detection in microscopically small areas. The intrinsic characteristics of the synchrotron radiation (high intensity, polarization and natural collimation) make possible to improve the sensitivities in comparison with the use of conventional sources . Micro-pixels mapping of X-ray fluorescence intensities or concentrations in many variety of samples can be fast completed without intricate experimental set-up.Some selected research activities carried out at the x-ray microprobe station of the XRF beamline of the LNLS , as well as a recently developed instrumentation that combine x-ray microbeam excitation and x-ray fluorescence detection at small take-off angles (grazing-exit geometry), will be shown in this work.One research activity will be focused on the evaluation of environmental pollution sources by the micro-XRF analysis of different individual particles collected from coarse air suspended particle material. Another subject of this work will pretend to show some results from the study of the 2D spatial distribution of arsenic in different rats tissues after exposure to inorganic arsenic. This subject is as part of a more general research being performed to develop reliable animals models of hydroarsenicism, which is related to several internal cancers in human being that had exposed to arsenic by naturally contaminated drinking water. Finally, preliminary results obtained from the measurements of specially prepared stepped multilayer samples, using the combination of x-ray microbeam excitation and grazing-exit x-ray fluorescence detection will be given. This must be considered as the first steps toward using this set-up to develop experiments in which the reconstruction of 3D elemental distributions in thin samples is required.  B. M. Gordon and K. W. Jones, Nucl. Instrum. Methods B, 10/11, 293 (1985). C. A. Pérez et al., X-Ray Spectrom., 28, 320-326 (1999).