Scanning Transmission Electron Microscope Independent Spectrometer Angular Range
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Solution Overview
Problem
Conventional scanning transmission electron microscopes face challenges in setting the optimum acceptance angular range for energy loss spectrometers independently of scattered electron detectors, leading to suboptimal scattered electron images, energy loss spectra, and element mapping images due to restricted mounting spaces and detector configurations.
Innovation Solution
The implementation of a scanning transmission electron microscope design featuring a first rotationally symmetric magnetic lens above the scattered electron detector and a second rotationally symmetric magnetic lens between the detector and the energy loss spectrometer, allowing independent setting of the acceptance angle and object point for the energy loss spectrometer, thereby enabling simultaneous acquisition of high-quality scattered electron images, energy loss spectra, and element mapping images without altering the energy loss spectrometer conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the distance between the scattered electron detector and the energy loss spectrometer is reduced and the aperture ratio is increased, then the acceptance angular ranges can be optimized, but the mounting space requirements and fabrication difficulty increase
Solution Approach 1:
The patent introduces adjustable rotationally symmetric magnetic lenses that provide dynamic control over the electron beam paths. The first lens dynamically adjusts the acceptance angular range for scattered electron imaging, while the second lens dynamically controls the object point formation for the energy loss spectrometer. This dynamic adjustment capability allows optimization of angular ranges without requiring fixed geometric constraints that would complicate fabrication.
Solution Approach 2:
The patent changes the optical parameters of the system by introducing magnetic lenses with adjustable focal lengths and strengths. By varying the magnetic field parameters of the two lenses, the system can optimize the acceptance angular ranges and object point formation without altering the physical geometry or mounting distances between components, thereby avoiding fabrication difficulties.
2Device complexity
If a single lens system is used to control both scattered electron detection and energy loss spectrometer, then the device complexity is reduced, but the ability to independently optimize acceptance angles and object points is lost
Solution Approach 1:
The patent segments the lens system into two independent rotationally symmetric magnetic lenses positioned at different locations: the first lens above the scattered electron detector and the second lens between the detector and energy loss spectrometer. Each lens independently controls specific optical parameters, enabling simultaneous optimization of scattered electron imaging and energy loss spectroscopy without requiring a complex single-lens system.
Solution Approach 2:
Each rotationally symmetric magnetic lens is designed to perform multiple functions: the first lens serves both scattered electron imaging and provides the object for the second lens, while the second lens simultaneously forms the object point for the energy loss spectrometer and maintains the electron beam transmission. This multi-functionality allows independent optimization without significantly increasing overall device complexity.
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 allows for independent setting of the acceptance angular range of the energy loss spectrometer, improving the signal-to-noise ratio and energy resolution of the energy loss spectrum without changing the conditions for the scattered electron detector, thereby enhancing the capability to extract information about the specimen's composition and structure.
Implementation Method 1
a first rotationally symmetric type magnetic lens for setting an acceptance angle of a scattered electron is disposed above a scattered electron detector
Implementation Method 2
a first rotationally symmetric type magnetic lens for setting an acceptance angle of a scattered electron is disposed above a scattered electron detector
Implementation Method 3
a second rotationally symmetric type magnetic lens is disposed between the scattered electron detector and the energy loss spectrometer
Implementation Method 4
a second rotationally symmetric type magnetic lens is disposed between the scattered electron detector and the energy loss spectrometer
Data Source
AI summary
The present invention provides a scanning transmission electron microscope which is capable of setting an acceptance angular range of an energy loss spectrometer independent of an acceptance angular range of a scattered electron detector, and makes it unnecessary to change a condition for the energy loss spectrometer with respect to a change in the acceptance angular range of the scattered electron detector. In such a scanning transmission electron microscope equipped with the energy loss spectrometer, a first rotationally symmetric type magnetic lens for setting an acceptance angle of an electron scattered by a specimen is disposed above the scattered electron detector for detecting the electron, a second rotationally symmetric type magnetic lens is disposed between the scattered electron detector and the energy loss spectrometer, the first rotationally symmetric type magnetic lens sets the acceptance angle of the scattered electron, and the second rotationally symmetric type magnetic lens sets an object point of the energy loss spectrometer.