Rotating Sample Holder for Random-Angle Tomography Imaging
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Solution Overview
Problem
Conventional electron tomography methods face limitations in the range of tilt angles and precision in setting angles, particularly in back-and-forth tilt protocols, which can be time-consuming and not optimal for radiation-sensitive samples, necessitating alternative approaches for improved reconstruction quality and dynamic sample imaging.
Innovation Solution
Random angle sampling in tomographic acquisition using stroboscopic charged particle beam exposures with a rotating sample holder, allowing continuous rotation and variable pulse rates to acquire images at multiple angles, enabling precise determination of relative and absolute angles for enhanced reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional back-and-forth tilt protocols are used, then angle setting is possible, but time consumption increases due to multiple starts and stops
Solution Approach 1:
The patent implements continuous periodic rotation of the sample holder instead of back-and-forth tilting. The sample holder rotates continuously through multiple revolutions, and images are acquired at specific phases during rotation, eliminating the need for repeated starts and stops while maintaining precise angular sampling through phase-locked detection
Solution Approach 2:
The system transitions from static step-by-step angular positioning to dynamic continuous rotation. The sample holder rotates at controlled speeds with variable pulse rates, allowing the system to adapt acquisition timing to the rotational phase, thereby reducing acquisition time while maintaining operational precision
2Object-affected harmful factors
If conventional ascending angular sampling is used, then systematic angle coverage is achieved, but radiation damage increases for sensitive samples
Solution Approach 1:
The continuous periodic rotation allows images to be acquired at specific phases corresponding to desired angular positions. By synchronizing image acquisition with rotational phase rather than using systematic ascending steps, the method reduces cumulative radiation exposure while maintaining comprehensive angular coverage for reconstruction
Solution Approach 2:
The system skips intermediate angular positions that would require prolonged exposure in conventional methods. By rotating continuously and acquiring images only at critical phases, the method rushes through unnecessary angular positions, minimizing radiation exposure while preserving essential structural information
3Measurement precision
If stroboscopic exposures with rotating sample are used, then random angle sampling is enabled, but image blur increases if exposure duration is too long
Solution Approach 1:
The stroboscopic method uses periodic pulsed illumination synchronized with the rotational period of the sample holder. By delivering brief pulses at specific phases during each rotation cycle, the system achieves precise angular sampling while limiting exposure duration to prevent motion-induced blur
Solution Approach 2:
The system pre-synchronizes the timing of exposure pulses with the rotational phase of the sample holder. By anticipating the exact moment when the sample reaches the desired angular position and delivering the pulse at that precise moment, the method achieves sharp images without requiring long exposures
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 method improves reconstruction quality and allows for the imaging of dynamically deforming samples by enabling a broader range of angles and reducing sample degradation, while optimizing exposure times to prevent image blur.
Implementation Method 1
stroboscopic charged particle beam (CPB) exposures of a rotating sample holder permit random angle sampling in tomographic acquisitions
Implementation Method 2
The sample is illuminated with a plurality of electron beam pulses at a pulse rate and while the sample is rotating
Implementation Method 3
determining the relative angle of the sample in each acquired image includes reading an encoder coupled to a rotatable sample holder at the time of acquisition
Data Source
AI summary
A sample holder retains a sample and can continuously rotate the sample in a single direction while the sample is exposed to a charged particle beam (CPB) or other radiation source. Typically, the CPB is strobed to produce a series of CPB images at random or arbitrary angles of rotation. The sample holder can rotate more than one complete revolution of the sample. The CPB images are used in tomographic reconstruction, and in some cases, relative rotation angles are used in the reconstruction, without input of an absolute rotation angle.