Electron Diffraction Tilt Series for Wide-Range Crystal Structure Solving
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Solution Overview
Problem
The dynamic range of conventional detectors is insufficient to accurately capture the wide range of intensities in electron diffraction patterns, particularly for large unit cells, leading to saturation of lower-resolution diffraction spots and incomplete data acquisition.
Innovation Solution
Acquire electron diffraction patterns at multiple electron doses and magnifications to construct high-resolution and low-resolution datasets, merging these in reciprocal space to overcome detector limitations and capture a broader range of diffraction spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single electron dose is used for diffraction pattern acquisition, then the acquisition process is simple, but the detector saturates at high-intensity central spots and loses low-resolution diffraction spots
Solution Approach 1:
The patent divides the diffraction pattern acquisition into multiple segments by using different electron doses for different regions. High electron dose is used for low-resolution spots while low electron dose is used for high-resolution spots, preventing detector saturation and preserving measurement precision across the entire dynamic range
Solution Approach 2:
The patent changes the electron dose parameter during the acquisition process. By adjusting the electron dose to be higher for certain patterns and lower for others, the system captures the full dynamic range of diffraction intensities without saturating the detector, thereby maintaining measurement precision
2Reliability
If high electron dose is used for all diffraction patterns, then sufficient signal is obtained, but radiation damage to the crystal increases and low-resolution spots are lost due to saturation
Solution Approach 1:
The patent applies partial action by using high electron dose only where necessary (for low-resolution spots that require stronger signal) and low electron dose elsewhere (for high-resolution spots and to minimize radiation damage). This selective approach maintains signal quality while reducing overall radiation exposure to the crystal
Solution Approach 2:
The electron dose parameter is dynamically adjusted based on the specific diffraction pattern and resolution requirements. By changing the dose parameter between acquisitions, the system optimizes signal quality for each pattern while minimizing cumulative radiation damage to the crystal
3Object-affected harmful factors
If low electron dose is used for all diffraction patterns, then radiation damage is minimized, but the signal intensity is insufficient and low-resolution spots cannot be detected
Solution Approach 1:
The patent segments the diffraction data collection into multiple acquisitions with different electron doses. Low electron dose is used for patterns requiring minimal radiation exposure, while high electron dose is used for patterns where strong signal is critical for detecting low-resolution spots, ensuring both radiation protection and detection capability
4Ease of operation
If single magnification is used for diffraction pattern acquisition, then the acquisition process is simple, but both high-resolution and low-resolution spots cannot be captured simultaneously within the detector dynamic range
Solution Approach 1:
The patent adds the dimension of multiple magnifications to the acquisition process. By collecting data at both high and low magnifications, the system captures diffraction spots across the full resolution range that would be impossible to obtain at a single magnification level, preventing information loss
Solution Approach 2:
The patent segments the magnification setting into multiple levels (high and low) to capture different resolution ranges. High magnification captures high-resolution spots while low magnification captures low-resolution spots, ensuring complete information acquisition across the entire resolution spectrum
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
Enables accurate determination of molecular structures by capturing diffraction spots with a wide range of intensities and resolutions, avoiding detector saturation and complex image processing, thus enhancing the precision of crystal structure analysis.
Implementation Method 1
Molecular structure of crystalline sample can be obtained by analyzing electron diffraction tilt series of crystals
Implementation Method 2
electrons scattered from the crystal are acquired from the side opposite to the electron source
Data Source
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AI summary
Molecular structure of a crystal may be solved based on at least two diffraction tilt series acquired from a sample (14). The two diffraction tilt series include multiple diffraction patterns of at least one crystal of the sample acquired at different electron doses. In some examples, the two diffraction tilt series are acquired at different magnifications.