Bifocal Multibeam System for Simultaneous 3D Diffraction Data Acquisition
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Solution Overview
Problem
Current methods for acquiring 3D diffraction data are time-consuming and prone to sample radiation damage due to frequent switching between diffraction and imaging modes, leading to crystal shift and reduced quality of diffraction patterns.
Innovation Solution
A bifocal multibeam charged particle system splits charged particles into two beams with different focal planes, allowing simultaneous acquisition of diffraction patterns and sample images using a bifocal beamformer, which tracks and corrects crystal position, reducing data acquisition time and radiation damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the imaging system switches frequently between diffraction mode and imaging mode to correct crystal shift, then the crystal position can be tracked and corrected, but the total data acquisition time increases and sample radiation damage increases
Solution Approach 1:
The patent combines diffraction pattern acquisition and sample image acquisition into a single simultaneous process using a bifocal beam splitter. The beam splitter divides the incident electron beam into two paths: one for diffraction and one for imaging, allowing both functions to be performed at the same time without mode switching, thereby reducing total acquisition time while maintaining crystal position tracking capability
Solution Approach 2:
The patent implements continuous crystal position tracking by acquiring sample images continuously during diffraction data acquisition without interrupting the diffraction measurement. This continuous monitoring and correction approach eliminates the need to stop for separate imaging measurements, maintaining uninterrupted useful action and reducing total acquisition time
2Reliability
If the incident beam size is increased to cover the crystal, then the crystal shift can be accommodated, but the diffraction pattern quality decreases due to increased background noise
Solution Approach 1:
The patent uses real-time feedback from continuously acquired sample images to monitor crystal position and dynamically adjust the beam position or sample stage position to keep the crystal centered in the narrow beam. This feedback mechanism allows the use of a narrow beam for high diffraction quality while maintaining reliable crystal positioning through active correction
Solution Approach 2:
The system uses the sample image acquisition path to provide self-correction information about crystal position drift. The crystal position is tracked using the same beam and detection system, allowing the system to self-correct positioning errors without external intervention or separate measurement systems
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 enables high-quality 3D diffraction data acquisition with reduced total acquisition time and minimized sample damage by tracking and correcting crystal shifts in real-time, maintaining a narrow incident beam and reducing background noise.
Implementation Method 1
The bifocal beamformer may individually apply a quadrupole field on one or both of the first and second charged particle beams
Implementation Method 2
the bifocal beamformer may individually deflect one or both of the first and second charged particle beams
Implementation Method 3
acquiring a diffraction pattern by irradiating a region of interest (ROI) of the sample with the first charged particle beam
Implementation Method 4
acquiring a sample image by irradiating the ROI with a second charged particle beam
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Diffraction patterns of a sample at various tilt angles are acquired by irradiating a region of interest using a first charged particle beam. Sample images are acquired by irradiating the region of interest using a second charged particle beam. The first and second charged particle beams are formed by splitting charged particles generated by a charged particle source.