EDXRF
Energy Dispersive XRF instruments were created shortly after the invention of semiconductor detectors. EDXRF spectrometers are comparatively simpler than the Wavelength Dispersive spectrometers. The capability of sorting the measured x-rays by energy eliminates the need for sophisticated goniometers and x-ray alignment. However, EDXRF spectrometers have a worst energy resolution, thus making difficult to resolve some natural spectral interferences, such as Ag-Ka / Pb-La, Fe-Kb – Co-Ka.
The use of radioisotope sources for excitation has declined due to their inherent disadvantages (radiation exposure, decay of activity) and the developments in x-ray tube design have made this option the preferred for excitation. Excitation radiation is commonly modified by using filters or secondary targets, as to increase the signal to noise ratio for selected elements.
The instrument available at NSIL has the following characteristics:
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x-ray tube
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Anode material
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Dual Sc-W
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Max. HV (kV)
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100
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Max current (mA)
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6
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Excitation spectrum modifiers
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8 secondary targets
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Detector
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Extended efficiency Ge
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Energy resolution (eV):
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140
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Sample holder:
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Stainless steel, robotic arm
based changer
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Calibrations for quantitative analysis:
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Soil / sediments
APM on filters
Rare Earth on minerals
User developed, using different corrections
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Spectra export:
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Yes
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Publication of interest:
· The application of XRF and PIXE in the analysis of rice shoot and compositional screening of genotypes, NIMB 371 (2016) 407–412
· XRF to support food traceability studies: Classification of Sri Lankan tea based on their region of origin, X-ray spectrometry 46 (2017) 220-224. doi:10.1002/xrs.2748
Use of geochemical fingerprints to trace sediment sources in an agriculture catchment of Argentina, FAO. 2019. Proceedings of the Global Symposium on Soil Erosion 2019. Rome, pp. 289-293
