Quantitative 3D Compositional Imaging and Analysis
with Atomic Resolution.
Instrument Description: (taken in part from Imago Scientific
Instruments)
An atom probe specimen is a small pointed tip (microtip) with a ~100nm
radius of curvature. A positive voltage is applied to the specimen
causing ionization of the surface atoms. Under an applied voltage
pulse or laser pulse, the positive ions are "evaporated" from the
surface of the sample. Time-of-flight mass spectrometry identifies
individual atoms by their elements or isotopes, while point-projection
microscopy identifies where atoms were originally located in the
specimen. The LEAP uses the principles of both time-of-flight mass
spectroscopy and point-projection microscopy to identify individual
elements and to locate them within the bulk of a material and build a
3-D image of sample material.
