THE TOMOGRAPHIC ATOM-PROBE - A 3-DIMENSIONAL NANOANALYTICAL TOOL ON ASUBNANOMETRIC SCALE

The Tomographic Atom-Probe is a quantitative microanalytical instrumen t which provides three-dimensional maps of chemical heterogeneities in a metallic material on a subnanometric scale. The basic principle of this new generation of apparatus relies on field evaporation of materi al and the localisation of evaporated atoms on a position-sensitive mu ltidetector. Chemical Species are identified by time-of-flight mass sp ectrometry. 3D-reconstructed images of a nickel base alloy containing very fine particles (similar to 7 nm) are presented and illustrate the performance of the instrument.