Building a Library of Simulated Atom Probe Data for Different Crystal Structures and Tip Orientations Using TAPSim

Abstract

The process of building an open source library of simulated field desorption maps for differently oriented synthetic tips of the face-centered cubic, body-centered cubic, and hexagonal-close-packed crystal structures using the open source software TAPSim is reported. Specifically, the field evaporation of a total set of 4 × 101 single-crystalline tips was simulated. Their lattices were oriented randomly to sample economically the fundamental zone of crystal orientations. Such data are intended to facilitate the interpretation of low-density zone lines and poles that are observed on detector hit maps during Atom Probe Tomography (APT) experiments. The datasets and corresponding tools have been made publicly available to the APT community in an effort to provide better access to simulated atom probe datasets. In addition, a computational performance analysis was conducted, from which recommendations are made as to which key tasks should be optimized in the future to improve the parallel efficiency of TAPSim.

3D nanostructural characterisation of grain boundaries in atom probe data utilising machine learning methods

“…TAPSim [31] was then used to simulate the field evaporation process. As detailed in [32–34], this requires the definition of a cascading mesh of integration points. At its finest scale, the mesh resolves the nanoscale dimensions and atomic structure of the specimen.…”

“…Such setup of 48.4 × 10 6 ions would have caused an impractical long and computational costly simulation. In fact, even for parallelized execution and assuming an optimistic evaporation rates (300 atoms per minute [34]) such simulation would have taken at least 112 days.…”

On Open and Strong-Scaling Tools for Atom Probe Crystallography: High-Throughput Methods for Indexing Crystal Structure and Orientation

“…As the last verification, we attempt indexing a synthetic polycrystal. For this purpose we built a needle-shaped synthetic dataset with approximately 200 × 10 6 atoms [47,77]. Grains with an average spherical equivalent diameter of 200 Å were created by placing seed points of a three-dimensional Poisson-Voronoi tessellation [114] inside the dataset.…”

“…A working strategy for extracting crystallographic information from datasets of single-and polycrystalline specimens is to evaluate the pattern in the hit densities in detector space. Such patterns are characterised by averaging a number of subsequent x and y detector hit positions from a few hundred thousand to a few million ions into a hit density pattern [32,[44][45][46][47]. Such patterns form as a result of trajectory aberrations inherently related to the crystallography of the specimen and quantum effects [48,49].…”

A Bottom-Up Volume Reconstruction Method for Atom Probe Tomography

“…Atomistic simulations (Vurpillot et al, 1999; Oberdorfer & Schmitz, 2011; Oberdorfer et al, 2013) were also built to simulate the tip evaporation process and correlate the emission positions to impact positions. The local field variation due to the geometry change can be accounted for via atomic simulations (Oberdorfer et al, 2013; Rolland et al, 2015 b ; Kühbach et al, 2019). Most of the approaches provide useful guidelines for improving the reconstructions.…”