Skip to main content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

3D Atom Probe Tomography


The LEAP 4000X is a three-dimensional atom probe microscope which provides nano-scale surface, bulk and interfacial materials analysis of structures with atom-by-atom identification and spatial positioning. The technique is based upon the principle of field evaporation, where a strong electric field is sufficient to cause the removal of atoms by ionization from a very sharp tip. Repetition of a pulsed voltage or laser progressively removes atoms from the apex of the specimen one-by-one. The atoms leaving the specimen surface are detected by a position-sensitive imaging mass spectrometer and recorded. The time-series data-set collected is reconstructed into an atomic scale 3-dimensional model or tomograph of the specimen Specimens are typically in the form of micrometer long needle shaped object with a tip diameter less than about 200 nm and a radius of curvature of about 100 nm. Specimen preparation often includes electropolishing for metals or FIB milling for any solid bulk specimen.

Scientific Opportunities/Applications

Interface characterization
3D elemental distributions
Compositional analysis
Precipitate characterization
Grain and phase boundary analysis
Cluster and nucleation distributions
3D device characterization

Usage Information

Access Information

Collaborative research projects are possible when the work is consistent with the Surface and Microanalysis Science Division interests. See contacts on the right to discuss possible collaborations

Created January 11, 2012, Updated February 22, 2017