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14. Jan. 2022

New equipment highlight in physical analytics: The Leibniz-IWT is now equipped with a new cryogenic LEAP 5000 XR tomographic atom probe from CAMECA. Capable of mapping in three dimensions the distribution of atoms in diverse materials using voltage and laser pulses, this technique enables the investigation of unforeseen mechanisms operating in the matter at the atomic-scale. For most sensitive specimens requiring protective atmospheres and/or cryogenic conditions, a brand-new cryogenic high-vacuum transfer module has been appended. Thereby, uncharted and challenging questions (e.g. concerning hydrogen tracing, frozen liquids etc.) can be explored.

APT (atom probe tomography) is the only atomic-scale characterization technique able to generate 3D information about atomic structure and provide chemical composition measurements with a sensitivity reaching parts per million for all elements, including light elements such as hydrogen.

APT essentially involves the physics of atom field evaporation applied to needle-shaped specimens with a radius of curvature less than 100 nm. Evaporated surface ions are projected onto a time-resolved and 2D highly sensitive detector coupled with a time-of-flight mass spectrometer. The obtained data sets contain typically several tens of millions of atoms. The 3D reconstructed volume of the field-evaporated needle-shaped specimen displays the 3D compositional map with a sub-nanometer spatial resolution, allowing fine-scale analysis of local chemical heterogeneities correlated with microstructural defects (dislocations, stacking faults and twins, grain boundaries, secondary phases and phase boundaries).

The high end LEAP 5000 XR installed at Leibniz-IWT is capable of analyzing most types of materials: from advanced metallic alloys, coatings, mineralogical samples to ceramics and much more, thanks to the two different operation modes using either voltage or laser pulses. This is especially relevant for IWT’s cooperation in the context of the interdisciplinary MAPEX Center for Materials and Processes at the University of Bremen.

Additionally, one special feature of the installed equipment lies in its high-vacuum cryo-transfer module, preventing chemical and structural changes during the specimen transfer from focused ion beam – scanning electron microscopes (FIB-SEM) for preparation to the APT. Thereby, uncharted physical questions bringing into play oxidation-sensitive materials or unintended ambient temperature diffusion, as well as fragile materials, can be investigated. This will be of particular interest for the future research and development in the field of hydrogen-based technologies and related topics at Leibniz-IWT. In this context, the Institute would like to thank the State of Bremen for its support.