We present a novel focused ion beam (FIB) method (METIS-Fa: multi-technical measurements of electron transparent materials using an In sandwich-a FIB approach), for preparing geometrically symmetric atom probe tomography (APT) needles from ∼70 to 100 nm thin transmission electron microscopy (TEM) FIB foils. The METIS-Fa method uses a FIB instrument and In to bolster the TEM foil for subsequent production of APT needles. This method is the first to enable geometrically symmetric APT sample preparation, allowing optimal conditions for each technique in a correlated, site-specific TEM and APT study, with an overall 66% success rate out of nine needles. METIS-Fa was tested on a synthetic basaltic silicate; epoxy; terrestrial silicate (San Carlos Olivine) and oxide (corundum); meteoritic silicates from Miller Range (MIL) 090019 and Acfer 094; and a presolar stardust grain from the meteorite Allan Hills (ALH) 77307. The extraterrestrial grains demonstrated the ability to target individual grains (>100 nm in size). The high-quality TEM and APT data presented in this study demonstrates the method's reproducibility and benefits. METIS-Fa provides access to atomic, trace element, and mineralogical characterization of organic and inorganic materials, with broad applicability to material science, geosciences, planetary science, and medical science.
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