Approaches for Promoting Accurate Atom Probe Reconstruction

Comparison of atom probe tomography (APT) results from different instruments, different users, or different samples requires confidence in overall reconstruction accuracy. The conventional reconstruction algorithm utilizes a single point-projection onto a spherical surface [1,2]. Although there are a limited number of parameters used to prescribe how detector events are converted to a 3D set of reconstructed coordinates, some constraints are necessary to ensure minimal precision and accuracy. Key inputs in the reconstruction algorithm used in the commercially available IVAS software (CAMECA Instruments, Inc.) include ionic volume, detection efficiency, image compression factor (ICF), either tip radius (initial or final) or the product of geometrical field factor (k) and evaporation field (F), sphere-to-cone ratio, and radial evolution procedure (voltage, shank angle, or tip profile) [3]. When quality protocols are implemented, reliable comparisons can be made [4]. The available approaches for properly choosing reconstruction parameters will be the focus of this presentation.