Synchrotron radiation micro-X-ray fluorescence analysis: A tool to increase accuracy in microscopic analysis
Microscopic X-ray fluorescence (XRF) analysis has potential for development as a certification method and as a calibration tool for other microanalytical techniques. The interaction of X-rays with matter is well understood and modelling studies show excellent agreement between experimental data and calculations using Monte Carlo simulation. The method can be used for a direct iterative calculation of concentrations using available high accuracy physical constants. Average accuracy is in the range of 3-5% for micron sized objects at concentration levels of less than 1 ppm with focused radiation from SR sources. The end-station ID18F of the ESRF is dedicated to accurate quantitative micro-XRF analysis including fast 2D scanning with collection of full X-ray spectra. Important aspects of the beamline are the precise monitoring of the intensity of the polarized, variable energy beam and the high reproducibility of the set-up measurement geometry, instrumental parameters and long-term stability.