Header Bild

Department Physical Metallurgy and Materials Testing

Atom probe tomography

For the characterization of materials with near-atomic resolution, Atom Probe Tomography (APT) is of special interest. For such examinations are an atom probe 3DAP type of Oxford Nanoscience Ltd. as well as a LEAP 3000X HR Imago are available. A very sharp tip is subjected to a high DC voltage (5-20kV), applied via an ultra-fast voltage pulse or an ultra-fast laser pulse. Due to the electrostatic field at the tip, surface atoms or ions are evaporated. Afterwards these atoms/ions are projected onto a position sensitive detector. The detector measures simultaneously the time to flight and the positions of the atoms in the tip. A reconstruction can be done, obtaining a 3D image of the analysed tip with information of the entire chemical composition. Almost the entire periodic system can be analyzed by this technique. By the use of a laser pulse, materials with poor electrical conductivity can also be analyzed.

Main applications: precipitation reactions, grain boundary segregation, phase analysis, Principal applications are: chemical analysis of materials at the atomic level, ion implantation, chemical clustering, 3D reconstruction of atoms.

Technical data:

LEAP 3000x HR:

  • Temperature range: 20K to 120K
  • Image gas: Helium, Neon

  • Field of View: ? 200 nm
  • Mass Resolution: FWHM=1100

3DAP:

  • Temperature range: 20K to 120K
  • Image gas: Argon, Helium, Neon

  • Field of View: ? 100 nm
  • Mass Resolution: FWHM=800