Berlin 2018 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 10: Spectroscopy and Microscopy I with X-rays and Ions
KFM 10.7: Vortrag
Dienstag, 13. März 2018, 12:00–12:20, EMH 225
Simulation of Large Solid Angle Effects for XRF Quantification - First Results — •Hanna Dierks1, Lars Lühl1, Konstantin Andrianov2, Thomas Wilhein2, and Birgit Kanngießer1 — 1AG Kanngießer, IOAP/TU Berlin — 2Institute for x-optics, Hochschule Koblenz
Soft and tender X-ray microscopy (XRM) at cellular level is used worldwide to investigate biomedicine samples. Scanning transmission X-ray microscopy (STXM) in combination with fluorescence detection is able to map elements from C to Mo with a lateral resolution below 100 nm. Since biological samples generally emit rather weak fluorescence signals, a high detector efficiency (e.g large solid angle) is necessary to avoid long measurement times. The AnImaX endstation is equipped with a new annular QUAD detector which yields a very large solid angle of detection (up to 1.2 sr). Established quantification approaches normally assume a small detector area with respect to the distance sample to detector, limiting the solid angle. For large solid angles, new effects occur, since the detected radiation passes a wide angular range on its way out of the sample. This results in geometrically different exit path lengths and, for inhomogeneous samples, even different sample composition (resp. absorption coefficients). In the following, these effects are simulated based on the Sherman equation combined with an additional virtual decomposition of the sample and detector. These forward calculations aim as a first step towards the development of new quantification concepts for annular detectors with a large solid angle.