EDAX NPARTM (Neighbor Pattern Averaging & Reindexing) is an advanced method for determining crystallographic orientation from electron backscatter diffraction (EBSD) patterns. Noise can degrade EBSD indexing performance by obstructing the detection of diffraction bands.
To achieve faster camera frame rates, the signal is amplified, which introduces noise into EBSD patterns. Even in the presence of significant noise, EDAX's sophisticated indexing and band detection algorithms function effectively.
However, when the noise level rises above acceptable bounds, indexing performance deteriorates and band detection becomes unreliable. By lowering the detector's gain and averaging several frames together, noise levels can be decreased. Both strategies, however, lengthen the acquisition time required for orientation mapping and EBSD pattern collection.
To index the gathered EBSD pattern, NPAR averages it with all of the nearby EBSD patterns on the mapping grid. Similar to frame averaging, but without the time penalty, this method lowers image noise.
This enhances the pattern's signal-to-noise ratio (SNR), enabling the EBSD detector to operate at higher gain settings without compromising indexing performance. NPAR allows for faster EBSD detector operation at a given beam current, lower beam currents and voltages, or improved data quality under conventional settings.
Features and Benefits
Improved Indexing Performance through Increased SNR
- Band detection and pattern indexing are improved by reducing temporal noise by averaging EBSD patterns with nearby patterns.
- Eliminates the time penalty associated with traditional frame averaging.
Faster Collection Speeds at any Given Beam Current
- Higher gains enable faster frame rates with effective indexing outcomes.
Operation at Lower Acceleration Voltages and Beam Currents
- Enhanced spatial resolution
- Perfect for samples that are beam-sensitive and non-conductive
Enhanced EBSD Image Quality Mapping
- Averaging patterns near grain boundaries enhances pattern overlap and improves image quality contrast compared to grain interiors.
Improved Orientation Precision
- Band detection and the ensuing orientation accuracy are enhanced by higher EBSD pattern SNR.
- Enhances the characterization of deformed materials when the step size is smaller than the deformation substructure scale.
Compatible with APEXTM EBSD and OIM AnalysisTM Software
- Users of OIM Analysis Data Collection can import patterns for NPAR indexing into OIM Analysis.