X-ray Detection Window for Backscattered Electron Rejection
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Solution Overview
Problem
Conventional X-ray detection systems in scanning electron microscopes face difficulties in distinguishing X-rays from backscattered electrons due to shared sensitivity, leading to superimposition issues and reduced collection efficiency, especially when a magnetic electron trap is not feasible or effective.
Innovation Solution
A method and device utilizing a holder with at least two windows of different transmission properties for backscattered electrons, positioning one window between the sample and the X-ray detection element to maximize X-ray transmission while minimizing backscattered electron transmission, allowing for qualitative and quantitative X-ray measurement without a magnetic electron trap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic electron trap is used to prevent backscattered electrons from entering the detector, then the detection of X-rays is improved, but the device complexity increases and the detector must be positioned relatively far from the sample reducing collection efficiency
Solution Approach 1:
The patent extracts and removes the magnetic electron trap from the detection system, replacing it with a simple window structure that physically blocks backscattered electrons while allowing X-rays to pass through. This eliminates the complex magnetic field generation equipment and simplifies the overall device architecture.
Solution Approach 2:
The patent introduces a window as an intermediary component between the sample and the detector. This window serves as a mediator that selectively transmits X-rays while blocking backscattered electrons, resolving the contradiction between needing electron rejection and maintaining detection efficiency without requiring complex magnetic traps.
2Productivity
If the detector is positioned close to the sample to increase solid angle and collection efficiency, then the measurement speed and statistics are improved, but the magnetic field of the electron trap affects the primary electron beam negatively
Solution Approach 1:
The patent removes the magnetic electron trap from the system, eliminating the source of magnetic field interference with the primary electron beam. This allows the detector to be positioned close to the sample without compromising beam quality, thereby improving measurement speed and statistics.
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-quality, quantitative X-ray measurement by significantly reducing the contribution of backscattered electrons, improving the signal-to-noise ratio and enabling detection of low-energy X-rays, thus enhancing the accuracy and clarity of sample composition analysis.
Implementation Method 1
one of the at least two windows is selected in such a way that in a predetermined energy range at each characteristic X-ray peak the greatest possible transmittance TX for X-rays and the transmittance TBSE for backscattered electrons is at most 0.1
Implementation Method 2
detecting the x-ray radiation by means of the x-ray detection element
Data Source
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AI summary
The invention relates to an energy dispersive detection method for X-radiation, comprising the following steps: irradiating a sample (20) with a primary electron beam (11) while exciting an emission of X-radiation (13) and back-scattered electrons (12); providing a means (34) for reducing the back-scattered electrons (12), said means comprising at least two windows (33) with different transmission properties for back-scattered electrons (12); positioning one of the at least two windows between an X-ray detection element (31) and a sample (20); and detecting the X-radiation (13) by means of the X-ray detection element (31). According to the invention, the one of the at least two windows (33) is selected such that in a predetermined energy range in at least one characteristic X-ray peak the transmittance Tx for X-rays is at a maximum and the transmittance TBSE for back-scattered electrons is not more than 0.1.