IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
artículos
Título:
Experimental Determination of RRS Cross Sections for Several Elements and Compounds
Autor/es:
H. J. SÁNCHEZ; M.C. VALENTINUZZI; C. A. PÉREZ; J. ABRAHAM
Revista:
AVANCES EN ANALISIS POR TECNICAS DE RAYOS X
Referencias:
Año: 2008 vol. 19 p. 327 - 332
ISSN:
1515-1565
Resumen:
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The x-ray resonant Raman effect takes places when
atoms are irradiated with an incident energy lower and close to an absorption
edge. This inelastic process can produce an important contribution to the
background of the fluorescent line. The resonant Raman effect must be taken
into account when samples of pure elements or constituted by elements with
proximate atomic number are analyzed because this effect affects the
determination of low concentration contaminants. The experimental values of
mass attenuation coefficients differ from the theoretical values when materials
are analyzed with monochromatic x ray beams under resonant conditions. The
resonant Raman scattering in part responsible for this difference.
Monochromatic synchrotron radiation was used to study the Raman effect on pure
samples of Mn, Fe and Cu and on oxides like Mn2O3, Fe2O3,
CuO and Cu2O. Energy scannings were carried out in different ranges
of energies near the absorption edge of the target element. Theoretical models
for the energy distribution of the Raman scattered photons, convoluted with the
instrument function, were used to determine the resonant Raman scattering cross-sections
as a function of the incident energy. The results indicate that RRS
cross-sections for pure samples are similar to those for oxides, showing that
the Raman scattering takes place in the same way in both kinds of samples.