Transmission Electron Microscopy Imaging With Dual Energy Filtering

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Solution Overview

Problem

In transmission charged particle microscopy, particularly in Single Particle Analysis, the low contrast of biological particles embedded in ice makes it difficult to recognize and identify them due to the use of light elements, and traditional methods like defocusing or phase plates either reduce high-resolution information or block beam intensity.

Innovation Solution

The method involves generating and recording two energy-filtered fluxes of charged particles: one consisting of non-scattered and elastically scattered particles, and another of inelastically scattered particles, which are combined to enhance contrast between particles and their ice surroundings, using an Electron Energy Loss Spectroscopy (EELS) module to filter out specific energy losses and create images with increased contrast.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If traditional methods like defocusing or phase plates are used to enhance contrast, then the visibility of particles is improved, but high-resolution information is reduced or beam intensity is blocked

Engineering Contradiction:

Improveimage contrastVSAvoidhigh-resolution information

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The electron beam flux is segmented into two distinct energy-filtered components: a first flux containing non-scattered and elastically scattered charged particles, and a second flux containing inelastically scattered charged particles. This segmentation allows each flux to contribute differently to image formation, with the first flux providing high-resolution structural information and the second flux providing contrast enhancement, thereby resolving the contradiction between contrast and resolution.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An Energy Filter (EELS module) is introduced as an intermediary device between the specimen and the imaging system. This filter selectively transmits charged particles based on their energy loss, allowing the first energy-filtered flux (minimal energy loss) to preserve high-resolution information while the second energy-filtered flux (higher energy loss) enhances contrast. The intermediary filter thus enables simultaneous achievement of both contrast enhancement and resolution preservation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If the specimen is made thinner to allow beam penetration, then transmission is improved, but contrast is reduced due to fewer scattering events

Engineering Contradiction:

Improvebeam transmissionVSAvoidimage contrast

Core Design Contradiction:

Use of energy by moving objectVSIllumination intensity

Solution Approach 1:

The invention changes the detection parameter from total scattered particle count to energy-loss-dependent particle classification. By using an Energy Filter to distinguish between particles with minimal energy loss (first flux) and those with higher energy loss (second flux), the method enables effective imaging of thin specimens where traditional contrast mechanisms fail. The parameter change allows thin specimens to be imaged by detecting subtle energy loss differences rather than relying on sufficient scattering events.

Inventive Principle:

Principle #35Parameter changes

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 improves the visibility of particles by leveraging the difference in inelastic scattering between particles and ice, even for very thin specimens, allowing for accurate identification and 3D reconstruction with enhanced contrast and signal-to-noise ratio.

Implementation Method 1

using an Electron EnergyLoss Spectroscopy (EELS) module to filter out specific energy losses and create images with increased contrast

Methodology Applied

Scientific EffectElectron Energy Loss Spectroscopy (EELS):

Implementation Method 2

one consisting of non-scattered and elastically scattered particles

Methodology Applied

Scientific EffectElastic scattering: Scattering

Implementation Method 3

another of inelastically scattered particles

Methodology Applied

Scientific EffectInelastic scattering: Scattering

Data Source

PatentUS11810751B2Method of imaging a specimen using a transmission charged particle microscope

Publication Date: 2023.11.07 FEI CO

AI summary

The disclosure relates to a method of imaging a specimen using a transmission charged particle microscope, said method comprising providing a specimen, and providing a charged particle beam and directing said charged particle beam onto said specimen for generating a flux of charged particles transmitted through the specimen. The method comprises the step of generating and recording a first energy filtered flux of charged particles transmitted through the specimen, wherein said first energy filtered flux of charged particles substantially consists of non-scattered and elastically scattered charged particles. The method as disclosed herein comprises the further step of generating and recording a second energy filtered flux of charged particles transmitted through the specimen, wherein said second energy filtered flux of charged particles substantially consists of inelastically scattered charged particles. Said first and second recorded energy filtered flux are then used for imaging said specimen with increased contrast.