3D- RIXS Analyzed by Multivariate Methods for Reveling Local Atomic Environments

D. PEREZ; JUAN JOSÉ LEANI; JOSE ROBLEDO; H.J. SÁNCHEZ

Campinas

Congreso; Annual Users´ Meeting of the Brazilian Synchrotron Light Laboratory; 2017

Brazilian Synchrotron Light Laboratory

X-ray Fluorescence analysis at the micrometer level has developed quickly over the last few years, particularly due to the development of new optical devices and the availability of synchrotron facilities. One of the main reasons of this fast development is the use of capillary optics [1]. A micrometer volume, or ?confocal volume?, in spatially resolved measurements is possible by overlapping the focus of the optics on the excitation and detection channels. This experimental arrangement showed the capacity to provide three-dimensional information on the sample composition in the micrometer regime. The most important limitation of the current quantification procedures is the existence of light elements in the sample, since no signal is directly detected from them. This so-called ?dark matrix? is a relevant problem, being the most important restraint of this technique nowadays.During the last few years, several works have been shown the first applications of Resonant Inelastic X-ray Scattering (RIXS) for the discrimination, determination and characterization of chemical environments in a variety of samples and irradiation geometries [2-8].In this work, RIXS is used in a confocal setup with the aim of determining different compounds of the same element in a stratified sample. This allows revealing local atomic environments with 3D-resolution using a typical SSD detection system, with low-energy resolution.A depth scanning of multi-layer copper sample was carried out at the XRF-beamline of the Brazilian Synchrotron Light Laboratory (LNLS, Campinas) using polycapillary lenses in a confocal setup. The sample was irradiated with photons having a fixed monochromatic energy 10 eV below the K absorption edge of Cu. After the data processing using multivariate methods, as Partial Least-Squares (PLS) analysis, the results show a clear discrimination of the different compounds of copper.The outcome is significant since this novel RIXS tool allowed observing different oxide-layers, characterizing the compound present at a particular depth of the sample with micrometer resolution using a low-resolution energy dispersive system