Electron Diffraction Tomography for Nanocrystal Structure Analysis
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Solution Overview
Problem
Current methods for nanocrystal structure analysis using electron diffraction are time-consuming and limited by dynamic scattering, making it difficult to obtain complete 3D data sets from nanocrystals, especially for electron beam-sensitive materials, which hinders high-throughput analysis in fields like pharmaceuticals and nanoscience.
Innovation Solution
A method involving electron diffraction tomography with beam scanning and precession protocols to collect quasi-kinematical diffraction patterns from multiple discrete locations within a sample, using template matching for orientation and phase determination, and normalization of intensities to solve the crystal structure without the need for extensive tilting or cryopreservation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional TEM ED data collection techniques are used, then complete 3D ED intensities can be collected from single crystals, but the process is very time consuming and does not allow collection of complete 3D data on the same single crystal
Solution Approach 1:
The patent segments the data collection process by acquiring ED patterns from multiple discrete locations across the crystal rather than attempting to collect complete data from a single location. This allows parallel information gathering that reduces total acquisition time while maintaining completeness of the 3D diffraction data set.
Solution Approach 2:
The patent introduces spatial distribution as an additional dimension to the data collection approach. By collecting ED patterns from multiple locations in the crystal (adding a spatial dimension to the measurement), the method achieves complete 3D structural information more efficiently than traditional single-location methods.
2Measurement precision
If traditional ED methods are used on nanocrystals, then structural information can be obtained, but dynamic scattering causes poor quality diffraction intensities
Solution Approach 1:
The patent extracts the harmful dynamic scattering effects by using precession electron diffraction to obtain quasi-kinematical intensities. This approach separates the desired structural information from the unwanted dynamic scattering contributions, yielding cleaner diffraction data suitable for structure determination.
Solution Approach 2:
The patent changes the diffraction conditions by implementing precession electron diffraction, which modifies the illumination geometry and scattering conditions. This parameter change transforms the diffraction regime from purely dynamic to quasi-kinematical, improving intensity quality.
3Measurement precision
If extensive tilting is performed to obtain complete 3D data, then crystal structure can be determined, but beam-sensitive materials are damaged or destroyed
Solution Approach 1:
The patent performs preliminary data collection at multiple discrete locations before attempting to determine the crystal structure. By gathering diffraction information from multiple positions in advance, the method reduces the need for extensive subsequent tilting operations that would expose beam-sensitive materials to prolonged electron beam damage.
Solution Approach 2:
The patent collects diffraction data from more locations than the minimum single position, using a distributed sampling approach. This excessive sampling strategy ensures sufficient data completeness while minimizing the cumulative beam exposure at any single location, protecting beam-sensitive materials.
4Productivity
If high throughput analysis is implemented, then productivity increases, but measurement precision of crystal structure may be compromised
Solution Approach 1:
The patent merges multiple ED patterns from different discrete locations into a single comprehensive data set. This combination approach maintains high throughput by processing multiple locations efficiently while preserving measurement precision through the integration of information from all sampled positions.
Solution Approach 2:
The patent implements continuous data acquisition across multiple locations without interruption, maintaining steady electron beam operation. This continuous action approach maximizes productivity while ensuring consistent data quality through uniform measurement conditions across all sampled positions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces data acquisition time, enhances the quality of diffraction patterns, and allows for high-throughput analysis of nanocrystals, including beam-sensitive materials, by obtaining complete 3D structural information efficiently and accurately.
Implementation Method 1
electron diffraction (ED) is the method of choice to solve the structural problems at nanocrystal size, as electrons interact about 10 3 times more strongly with matter than X-rays
Implementation Method 2
the diffraction intensities which carry information about the crystal structure are of poor quality, due to multiple/ dynamical scattering of the electrons
Implementation Method 3
the electron beam is tilted by a small angle, typically 1-3 degrees, and then rotated around the TEM optical axis. In this way a volume of reciprocal space is recorded (integration over excitation error), and more importantly, the multiple/dynamic scattering is greatly reduced
Data Source
Figure 1
Figure 2A~2F
Figure 3A~3D
AI summary
The present invention relates to a method for calculating an orientation and phase map of a sample (38) comprising a plurality of crystals (36) in different orientations and different known phases, and a device for interfacing with a TEM to perform this and related methods.