Best Practices for Reporting Atom Probe Analysis of Geological Materials

Recent work has established atom probe tomography (APT) as a unique tool within the geosciences for interrogat­ ing material chemistry at the nanoscale. In APT, a needle‐ shaped specimen with an end‐form radius on the order of 50–100 nm is held at high voltage, and constituent atoms are field evaporated through application of a timed voltage pulse (for conductive materials) or laser pulse (for semicon­ ductors and insulators). The voltage bias and small radius of curvature produce a large electric field that is localized around, and diverging from, the end surface of the needle‐ shaped specimen; evaporated ions are accelerated by the local electric field, leading to divergent trajectories for ions originating from different positions on the specimen surface. A position‐sensitive detector records both the hit position of Best Practices for Reporting Atom Probe Analysis of Geological Materials