Atom Probe Tomography
For the characterization of materials with near-atomic resolution, Atom Probe Tomography (APT) is of special interest. For such examinations are an atom probe 3DAP type of Oxford Nanoscience Ltd. as well as a LEAP 3000X HR Imago are available. A very sharp tip is subjected to a high DC voltage (5-20kV), applied via an ultra-fast voltage pulse or an ultra-fast laser pulse. Due to the electrostatic field at the tip, surface atoms or ions are evaporated. Afterwards these atoms/ions are projected onto a position sensitive detector. The detector measures simultaneously the time to flight and the positions of the atoms in the tip. A reconstruction can be done, obtaining a 3D image of the analysed tip with information of the entire chemical composition.