Spatial resolution of confocal XRF technique using capillary optics
1 CNRS, UMR7325, Aix-Marseille Univ., CINaM, Marseille 13288, France
2 IFG-GmbH, Rudower Chaussee 29/31, Berlin 12489, Germany
Nanoscale Research Letters 2013, 8:271 doi:10.1186/1556-276X-8-271Published: 7 June 2013
XRF (X-ray fluorescence) is a powerful technique for elemental analysis with a high sensitivity. The resolution is presently limited by the size of the primary excitation X-ray beam. A test-bed for confocal-type XRF has been developed to estimate the ultimate lateral resolution which could be reached in chemical mapping using this technique. A polycapillary lens is used to tightly focus the primary X-ray beam of a low power rhodium X-ray source, while the fluorescence signal is collected by a SDD detector through a cylindrical monocapillary. This system was used to characterize the geometry of the fluorescent zone. Capillary radii ranging from 50 μm down to 5 μm were used to investigate the fluorescence signal maximum level This study allows to estimate the ultimate resolution which could be reached in-lab or on a synchrotron beamline. A new tool combining local XRF and scanning probe microscopy is finally proposed.