Berlin 2015 – wissenschaftliches Programm

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MI: Fachverband Mikrosonden

MI 2: Analytical Transmission Electron Microscopy and Atom Probe Tomography

MI 2.5: Vortrag

Montag, 16. März 2015, 13:00–13:15, EMH 225

Accurate volume reconstruction by numerical calculation of trajectories — •Daniel Beinke, Christian Oberdorfer, and Guido Schmitz — Institute of Materials Science, University of Stuttgart, Germany

A new approach for the reconstruction of atom probe data is presented. It is based on the calculation of realistic trajectories of evaporated ions. To this end, a Voronoi tessellation of the simulation space is used in order to bridge several orders of magnitude in distance. Compared to other reconstruction techniques, the order of reconstruction is inverted, which means that last detected atoms are reconstructed first. Consequently the emitter shape is known at each reconstruction step.

Based on numerical model emitters with particles or layers of heterogeneous evaporation threshold, we demonstrate that this new concept has indeed the natural potential to overcome artifacts of local magnification, such as depleted zones at interfaces or distorted particle shapes. Still issues in detail, scoping with the finite detection efficiency, finite aperture size, and the limitation in computing resources have to be resolved before practical application to experimental data sets.