Movable Electron Column for Ambient Sample Imaging
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Solution Overview
Problem
Conventional Environmental Scanning Electron Microscopes (ESEM) face limitations in examining untreated biological samples under natural ambient conditions due to pressure constraints in the sample chamber, which result in reduced signal quality and inability to maintain samples at room temperature without altering their environment.
Innovation Solution
The electron microscope features a movable electron column with a constant or tapering free diameter relative to the sample table, allowing samples to be examined at atmospheric pressure and room temperature, with a pressure-limiting diaphragm design that minimizes electron beam interaction with gas, ensuring focused electron beam delivery and enhanced secondary electron generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the pressure in the sample chamber is increased to examine untreated biological samples under natural ambient conditions, then the sample can be examined in its natural state, but the signal-to-noise ratio deteriorates due to electron scattering by gas molecules
Solution Approach 1:
The electron column is made movable along its longitudinal axis relative to the sample table, allowing dynamic adjustment of the electron beam path length through the gas-filled sample chamber. This enables optimization of the balance between maintaining ambient pressure for untreated samples and minimizing electron scattering to preserve signal quality
Solution Approach 2:
The system changes the physical parameter of electron beam energy and path length by moving the electron column, allowing examination of samples at different pressures and distances to optimize both sample condition preservation and signal quality
2Temperature
If the pressure in the sample chamber is increased to maintain samples at room temperature without evacuation, then the sample environment is preserved, but fewer primary electrons reach the focused point due to scattering
Solution Approach 1:
By making the electron column movable, the system can dynamically adjust the electron beam path length through the gas-filled chamber, compensating for electron scattering losses while maintaining room temperature operation and preserving sample integrity
3Area of stationary object
If the electron beam path through the gas-filled chamber is lengthened to improve sample coverage, then more areas can be examined, but electron scattering increases and reduces focusing quality
Solution Approach 1:
The movable electron column allows dynamic optimization of the beam path length, enabling the system to adjust between coverage area and focusing quality based on specific examination requirements, maintaining sharp focus even in atmospheric pressure conditions
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 design enables high-quality imaging of samples with improved signal-to-noise ratio and allows for dynamic experiments on untreated biological samples without altering their natural state, as most primary electrons strike the sample unscattered, generating a large number of secondary electrons and detecting low-energy electrons effectively.
Implementation Method 1
an electron source for generating an electron beam, an electron column through which the electron beam strikes a sample
Implementation Method 2
secondary electrons are generated by interaction with the primary electrons
Implementation Method 3
a detector for detecting low-energy electrons
Implementation Method 4
at least one pressure-limiting diaphragm arranged at the end of the electron column
Data Source
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AI summary
The invention relates to an electron microscope (1) comprising an electron source (2) for generating an electron beam (3), an electron column (4) through which the electron beam (3) strikes a sample (7) arranged on a sample table (6) in a sample chamber (5), at least one pressure-limiting aperture (8) arranged on an end side on the electron column (4), and a detector (9) for detecting low-energy electrons (10) generated from the sample (7). According to the invention, the electron column (4) has a clear diameter (11) which is either constant along the longitudinal axis (X) or tapers toward the sample chamber (5) and is designed to be moveable relative to the sample table (6) and independent from the detector (9) such that the sample (7) can be examined under atmospheric pressure and/or at room temperature. The invention additionally relates to a use of such an electron microscope (1). The invention further relates to a method for examining a sample (7) using an electron microscope (1), wherein an electron beam (3) is generated by an electron source (2), which is guided through an electron column (4) and at least one pressure-limiting aperture (8) to the sample (7) arranged on a sample table (6) in a sample chamber (5), from which low-energy electrons are created and detected by a detector (9).