Wien Filter Electron Energy Analyzer with Quadrupole Field Control
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Solution Overview
Problem
Conventional energy analyzers, such as electrostatic spherical analyzers and Wien filters, face limitations in achieving high energy resolution over a wide energy range due to their design, where electrostatic analyzers are unsuitable for rapid wide-range detection and Wien filters struggle to provide high energy resolution across all energy values.
Innovation Solution
An apparatus and method utilizing a Wien filter with a quadrupole field intensity adjustment and detector position synchronization to focus backscattered electrons on a detection surface, combined with an astigmatism correcting device and a shunt with slits to enhance energy resolution across a wide range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an electrostatic spherical analyzer is used to achieve high energy resolution, then the energy resolution is improved, but the detectable energy range becomes strictly limited
Solution Approach 1:
The patent combines a Wien filter (which provides energy dispersion) with an electrostatic spherical analyzer (which provides high energy resolution). The Wien filter disperses backscattered electrons by energy, and the electrostatic spherical analyzer then analyzes the dispersed electrons with high resolution. This merging allows the system to achieve both wide energy range detection and high energy resolution simultaneously.
Solution Approach 2:
The energy analysis function is segmented into two stages: first, the Wien filter performs preliminary energy dispersion to separate electrons by energy across a wide range; second, the electrostatic spherical analyzer performs detailed energy analysis on the dispersed electrons. This segmentation allows each component to specialize in one aspect, enabling both wide range and high resolution.
2Adaptability or versatility
If a Wien filter is used alone for energy analysis, then a wide energy range can be detected in parallel, but high energy resolution cannot be obtained for all energy values
Solution Approach 1:
The patent merges the Wien filter's wide energy range capability with the electrostatic spherical analyzer's high resolution capability. The Wien filter disperses electrons across a wide energy range in parallel, and the electrostatic spherical analyzer then provides high resolution analysis of the dispersed electrons, achieving both wide range and high resolution.
3Measurement precision
If serial detection is used to achieve high energy resolution, then the energy resolution is improved, but the measuring time increases
Solution Approach 1:
The detection process is segmented into two parts: the Wien filter performs parallel energy dispersion of all backscattered electrons simultaneously across a wide range, while the electrostatic spherical analyzer performs serial high-resolution analysis. This segmentation allows the system to maintain high resolution while reducing total measurement time compared to pure serial detection, as the Wien filter pre-sorts electrons by energy in parallel.
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 energy resolution over a wide energy range by focusing backscattered electrons on a detection surface, overcoming the limitations of conventional analyzers.
Implementation Method 1
a Wien filter configured to disperse the backscattered electrons... changing an intensity of a quadrupole field of the Wien filter
Implementation Method 2
a detector configured to measure the energy spectrum of the backscattered electrons dispersed by the Wien filter
Data Source
AI summary
The present invention relates to an apparatus and method for analyzing the energy of backscattered electrons generated from a specimen. The apparatus includes: an electron beam source (101) for generating a primary electron beam; an electron optical system (102, 105, 112) configured to direct the primary electron beam to a specimen while focusing and deflecting the primary electron beam; and an energy analyzing system configured to detect an energy spectrum of backscattered electrons emitted from the specimen. The energy analyzing system includes: a Wien filter (108) configured to disperse the backscattered electrons; a detector (107) configured to measure the energy spectrum of the backscattered electrons dispersed by the Wien filter (108); and an operation controller (150) configured to change an intensity of a quadrupole field of the Wien filter (108), while moving a detecting position of the detector (107) for the backscattered electrons in synchronization with the change in the intensity of the quadrupole field.