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Atom Probe Assist

Atom probe tomography (APT) is a material analysis technique that provides 3D chemical composition and imaging at the atomic scale and is uniquely suited to the analysis of grain boundary segregation. APT analysis requires sample preparation similar to transmission electron microscopy (TEM), but a needle geometry is required instead of a thin lamella. The feature must be within ≈ 500 nm of the tip apex to analyze site-specific features. Generally, a focused ion beam (FIB) instrument is used to prepare this type of specimen. In the final steps of the specimen sharpening, contrast in the FIB can become very low or negligible, making site-specific analysis challenging.

Atom Probe Assist


The EDAX Atom Probe Assist tool provides an innovative means of monitoring grain boundary positions between FIB milling steps. Because the APT sample tip is a small 3D cone, transmission-electron backscatter diffraction (t-EBSD) can measure and image the crystallographic orientation and determine grain boundary position. This tool is optimized for t-EBSD measurements of APT tips, including default map shapes corresponding to APT tip profiles and image processing procedures to enhance t-EBSD patterns from samples with varying sample thickness.

Traditional EBSD can be used to determine a sample's grain boundary position and character before initial site-specific FIB lift-out preparation, allowing for investigating specific grain boundary types. This is important as different boundary types have different segregation behavior affecting material performance. By collecting t-EBSD datasets between milling steps, the grain boundary position can be easily identified, and the milling procedure can be stopped when the boundary is within 200 nm of the sample tip. Preparation and validation can be completed in the FIB, eliminating the need to transfer the sample.

Features and benefits

Smart background processing
  • T-EBSD background processing is explicitly designed for optimized patterns from APT specimens of varying thickness to allow accurate characterization of orientations and grain boundary position
Smart camera optimization
  • Automated setup of camera parameters for the acquisition of high-quality t-EBSD patterns from APT specimens for accurate data collection
Smart indexing
  • T-EBSD pattern analysis using unique Triplet Indexing for improved indexing rates and spatial resolution on small-scale APT specimens
APT specimen tip mapping mode
  • Map shape template designed to match APT specimen tip shape for fast and efficient setup and data collection
  • Map shape easily adjustable for consistent mapping after specimen milling
  • Spatial indication of mapping dimensions to determine if a grain boundary is within the required distance from the specimen tip apex
Transmission-EBSD mode
  • T-EBSD mode sets up acquisition parameters to automatically collect quality data from t-EBSD specimens
  • Easily switch from t-EBSD to traditional EBSD collection to handle both APT specimen analysis and site-selection analysis


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