Confocal three-dimensional energy-dispersive micro x-ray diffraction with polycapillary optic

PEREZ, R.D.; SÁNCHEZ, H.J; SOSA, C.; PÉREZ C.A.

Figueira da Foz

Conferencia; European Conference on X-Ray Spectrometry (EXRS2010); 2010

The confocal setup consists of x-ray lenses in the excitation as well as in the detection channel. In this configuration, a micro volume defined by the overlap of the foci of both x-ray lenses is analyzed. Scanning this micro volume through the sample, 1-3 dimensional studies can be performed. For depth profiling studies, only the scan of the confocal volume in the normal direction to the sample is required. An elemental analysis is obtained by the detection of the x-ray fluorescence produced in the confocal volume. In addition, Energy Dispersive X-Ray Diffraction analysis (EDXRD) in the confocal volume can be performed using a continuous polychromatic source and an appropriated fixed geometry based on a low divergence optic. To implement the confocal setup, we used two monolithic semi-polycapillaries in the excitation and detection channel. The polycapillaries were made by means of drawing of multibundles of borosilicate glass capillaries in a heating furnace. Our last prototypes produced an average spot size of 70<m and an average transmission efficiency of 30%, which gives an average gain of 450. The experiment was carried out at the D09B beamline of the Brazilian Synchrotron Light Laboratory (Laboratório Nacional de Luz Síncrotron, LNLS) using white beam. A silicon drift X-ray detector of 150 eV resolution at 5.9 keV was used for detection of scattered photons. A detailed characterization of our confocal setup is described in this work. Structural micro-EDXRD analyses of several stratified samples are shown.