21-27 March 2009
Prague
Europe/Prague timezone

A Monte Carlo study for the X-ray fluorescence enhancement induced by photoelectron secondary excitation

24 Mar 2009, 08:00
1h
Prague

Prague

Prague Congress Centre 5. května 65, 140 00 Prague 4, Czech Republic
Board: Tuesday 055
poster Event Processing Poster session

Speaker

Dimosthenis Sokaras (N.C.S.R. Demokritos, Institute of Nuclear Physics)

Description

Well established values for the X-ray fundamental parameters (fluorescence yields, characteristic lines branching ratios, mass absorption coefficients, etc.) are very important but not adequate for an accurate reference-free quantitative X-Ray Fluorescence (XRF) analysis. Secondary ionization processes following photon induced primary ionizations in matter may contribute significantly to the intensity of the detected fluorescence radiation introducing significant errors in quantitative XRF analysis, if not taken into account properly. In the present work, a new developed particle/ray-tracing Monte Carlo (MC) simulation code is presented. The code implements appropriate databases for all the physical interactions that involve between x-rays, electrons and matter leading to the determination of the intensity of the characteristic radiation induced by photoelectrons for any given experimental conditions (sample geometry, incident beam parameters etc). In order to achieve acceptable counting statistics for the secondary photoelectron excitation, that it is a second order phenomenon, the MC simulation code is executed on a powerful cluster-computer facility, which is able to host long time simulations (up to 20 billion events per exciting energy) deducing thus low relative uncertainties. The final goal is to compare the simulated MC data together with high accurate experimental measurements, deduced from well and absolute calibrated experimental setups. In this way the current description of electron ionization cross sections can be properly assessed, whereas in the case that systematic differences are observed, it may lead to the determination of corrective electron ionization cross sections versus energy that fit properly the experimental data.
Presentation type (oral | poster) poster

Primary author

Dimosthenis Sokaras (N.C.S.R. Demokritos, Institute of Nuclear Physics)

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