TXRF is a micro-analytical tool. It allows multi-elemental determination in the low ppb range for elements Z &gt; 16 present in microgram amounts of sample material. It operates cost and maintenance efficient. Additionally, it is capable of direct analysis of samples in a solid state. Most critical to advance quality of TXRF analysis is a better understanding of absorption characteristics in samples, which exceed the critical thickness. This is critical in quantitative analysis, especially if external calibration is applied, for example in the detection of impurities in Si wafers. It is beneficial for such a quantitative analysis to be able to correct for these absorption errors. To gain better understanding of primary beam shading it needs diagnostics offering spatial resolved information of signal reduction of a specimen well defined in morphology and composition. The structural requirements are met by an array of pL-droplets from a Ni-standard solution. The microscopic observation of shading is achieved using a color X-ray camera with an ultrafast readout pnCCD detector chip and equipped with polycapillary optics provided full field spatial resolution. Ni array deposits were analyzed by (SR)-TXRF at BAMline @ BESSY II (Berlin, Germany). Measurements with advanced analysis provides a subpixel calculation model to improve the spatial resolution. This improvement can be seen in Figure 1. The experimental results are compared to three different calculation models with in general good agreement [1]. However, the comparison also points to parameters that are yet not well enough understood. [1] M. Menzel, O.Scharf, S. H. Nowak, M. Radtke, U. Reinholz, P. Hischenhuber, G. Buzanich, A. Meyer, V. Lopez, K. G. McIntosh, C. Streli, G. Havrilla and U. E. A. Fittschen, Shading in TXRF: Calculations and experimental validation using a color X-ray camera, J. Anal. At. Spectrom. (2015), just accepted DOI:10.1039/C5JA00127G

Overcoming the self-shading problem in TXRF: Diagnostics and solutions using pL-printing and a color x-ray camera

251st National Meeting (2016)

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