Application toward Confocal Full-Field Microscopic X-ray Absorption Near Edge Structure Spectroscopy
Pieter Tack1, Bart Vekemans1, Brecht Laforce1
1XMI, Department of Analytical Chemisty, Ghent University , Krijgslaan 281 S12, 9000 Ghent, Belgium.
Analytical Chemistry
|February 18, 2017
Summary
This study introduces a novel 3D X-ray absorption near edge structure (XANES) spectroscopy method using a pnCCD detector. This technique rapidly maps chemical states in 3D, outperforming conventional methods for various materials.
Area of Science:
- Materials Science
- Spectroscopy
- Chemistry
Background:
- X-ray absorption near edge structure (XANES) spectroscopy provides insights into local chemical structure and oxidation states.
- Conventional XANES mapping relies on scanning a focused X-ray beam, which is time-consuming.
- Existing full-field methods are typically transmission-based, limiting their application to thin samples.
Purpose of the Study:
- To develop a rapid, 3D spatially resolved XANES spectroscopy method.
- To overcome limitations of conventional and existing full-field XANES techniques.
- To demonstrate the applicability of the new method for chemical state analysis.
Main Methods:
- Utilized an energy-dispersive pnCCD detector (SLcam) for fluorescence detection.
- Implemented a confocal mode for 3D spatial resolution without sample rotation.
- Achieved significantly reduced measurement times compared to conventional methods.
Main Results:
- Successfully acquired 3D spatially resolved chemical state information.
- Applied the method to a gold-supported magnesia catalyst (Au/MgO) and Fe-rich inclusions in natural diamond.
- Obtained XANES spectra that matched reference spectra for fingerprinting and linear combination analysis.
Conclusions:
- The developed fluorescence-based confocal XANES method offers rapid and direct 3D chemical state mapping.
- This technique is suitable for analyzing complex samples, including catalysts and geological materials.
- The method enables effective fingerprinting and quantitative analysis of known chemical species.
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