Electron Beam Drift Compensation for Radiation-Sensitive Specimens
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Solution Overview
Problem
High-resolution electron microscopy is hindered by image drift, which causes blurring, and existing methods to compensate for drift require high radiation doses that damage radiation-sensitive specimens like biological molecules, rendering subsequent images unusable.
Innovation Solution
A drift-compensation algorithm that estimates drift without exposing radiation-sensitive specimens to high radiation doses by using a fast controllable beam deflector and a drift-estimation algorithm that locks on drift-induced motion, allowing imaging without initial high-dose exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a drift-estimation algorithm is used to obtain accurate drift estimate before counter-acting drift-induced motion, then image quality is improved, but radiation dose to the specimen increases causing irreversible damage
Solution Approach 1:
The patent divides the sample into different portions: a first portion used for drift estimation and a second portion (POI) used for high-resolution imaging. The drift-estimation algorithm processes image frames from the first portion to compute drift parameters, which are then applied to compensate motion during imaging of the radiation-sensitive POI. This segmentation allows drift compensation without exposing the sensitive specimen to high radiation doses.
Solution Approach 2:
The patent introduces an intermediary region (the first portion of the sample) that serves as a mediator between the drift compensation need and the radiation-sensitive POI. This intermediary portion absorbs the radiation dose required for accurate drift measurement, while the POI receives minimal radiation exposure. The drift information obtained from the intermediary is then used to protect the POI from motion blur.
2Manufacturing precision
If stage actuation is used to move the sample holder to counteract drift-induced motion, then image sharpness is improved, but system complexity increases
Solution Approach 1:
The patent replaces the mechanical stage actuation system with an electronic beam deflection system for drift compensation. Instead of physically moving the sample holder to counteract drift, the patent uses a beam deflector to dynamically adjust the electron beam position, effectively compensating for drift-induced motion through electronic control. This substitution reduces mechanical complexity while achieving the same image sharpness improvement.
3Measurement precision
If active optical control of electron-beam parameters is used to counteract drift, then image quality is improved, but control system complexity increases
Solution Approach 1:
The patent changes the parameters of the electron beam (position, angle) through the beam deflector to counteract drift-induced motion. By dynamically adjusting beam parameters in response to measured drift, the system achieves image stabilization without requiring complex mechanical stage control or sophisticated optical element manipulation. The parameter changes are computed from drift estimation and applied through relatively simple beam deflection control.
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 high-resolution imaging of radiation-sensitive specimens by minimizing specimen damage, achieving accurate drift compensation without initial high-dose radiation exposure.
Implementation Method 1
a fast controllable beam deflector and employs a drift-estimation algorithm that locks on the drift-induced motion when the beam deflector places the electron beam into a first position on the sample
Implementation Method 2
a charged particle beam column configured to direct a beam of charged particles to a sample; a detector configured to detect a response of the sample to the beam of charged particles
Data Source
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AI summary
In one example, a method performed via a computing device for providing support to a charged particle beam system includes computing a drift estimate based at least in part on a first set of image frames acquired with a charged particle beam column and a detector from a first portion of a sample. The method also includes configuring the charged particle beam column and the detector to acquire a second set of image frames from a second portion of the sample. The method further includes performing drift compensation during acquisition of the second set of image frames based at least in part on the drift estimate.