Grazing Exit X-ray Fluorescence Analysis (GE-XRF)

Grazing Exit XRF (GE-XRF) is a method related to TXRF. An X-ray beam irradiates the sample at normal incidence and the fluorescence radiation is detected under grazing angles. The use of normal incidence and grazing exit detection should reduce the self- absorption effects of the primary radiation.

 

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Fig.1: Schematic illustration of TXRF and GE-XRF geometry

GE-XRF is theoretically based on the reciprocity theorem. As a consequence of the detection of the emitted fluorescence intensity under grazing angles the scattered radiation is reduced and the signal of the sample can be measured almost without background. This geometry is - according to the reciprocity theorem - equivalent to the TXRF setup with the drawback of a lower sensitivity due to the much smaller solid angle seen by the detector. However, it offers the advantage of spatially resolved measurements. Similarly to TXRF, GE-XRF is applied to trace analysis of samples deposited on flat sample carrier and to thin film analysis.