Simultaneous X-ray and Backscattered Electron Detection
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Solution Overview
Problem
Existing detectors cannot simultaneously measure backscattered electrons and X-ray quanta in an energy-resolved manner due to an unfavorable signal ratio of photons to backscattered electrons, making it difficult to detect characteristic X-ray peaks amidst the dominant electron signal.
Innovation Solution
A detector with an energy-dispersive X-ray detector element and a means to reduce the contribution of backscattered electrons, such as a foil, is designed to allow simultaneous measurement by ensuring the number of backscattered electrons is in the same order of magnitude as X-ray photons, enabling the detection of X-ray peaks and subtracting the electron contribution from the spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an energy-dispersive X-ray detector is used to detect X-ray quanta, then energy resolution for X-rays is achieved, but the detector cannot simultaneously detect backscattered electrons due to the unfavorable signal ratio of photons to electrons
Solution Approach 1:
The detector is divided into two independent detection channels: one for X-ray photons and one for backscattered electrons. Each channel has its own signal processing path, allowing simultaneous detection of both particle types without interference. The electron channel includes an electron-to-photon converter that converts electron signals into photons detectable by the same semiconductor detector, while the X-ray channel directly detects X-ray photons.
Solution Approach 2:
An electron-to-photon converter is introduced as an intermediary component in the electron detection path. This converter transforms backscattered electrons into photons, which can then be detected by the semiconductor detector in the same manner as X-ray photons. This intermediary enables the detector to handle both electron and photon signals through a unified detection mechanism.
2Quantity of substance
If a flat semiconductor detector is used as a backscattered electron detector, then a large solid angle for detecting high intensity electrons is achieved, but no energy resolution is obtained
Solution Approach 1:
The detector merges the advantages of both BSE detectors (large solid angle, high signal intensity) and EDS detectors (energy resolution) into a single unified system. By combining the large-area semiconductor detector with electron-to-photon conversion capability and energy-dispersive signal processing, the system achieves both high signal intensity from the large detection area and energy resolution through spectral analysis of the converted signals.
3Measurement precision
If an electron trap is placed in front of the X-ray detector to prevent electrons from entering, then X-ray measurement is achieved, but backscattered electrons cannot be detected simultaneously
Solution Approach 1:
Instead of placing an electron trap to block electrons (as in conventional X-ray detectors), the invention inverts the approach by providing a dedicated electron detection channel that actively captures and converts electron signals. The detector design allows electrons to be detected through the electron-to-photon converter while X-rays are detected directly, eliminating the need for electron blocking and enabling simultaneous detection of both particle types.
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 setup allows for the simultaneous and separate recording of X-ray quanta and backscattered electrons, providing energy-resolved measurements with improved energy resolution for both, enabling qualitative and quantitative analysis with enhanced analytical significance.
Implementation Method 1
an energy-dispersive X-ray detector element for the detection of X-rays and backscattered electrons
Implementation Method 2
A detector with an energy-dispersive X-ray detector element and a means to reduce the contribution of backscattered electrons, such as a foil
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a detector (10) and a device for the simultaneous, energy-dispersive recording of backscattered electrons (5) and X-rays (7) after a sample (3) is excited with primary electrons (4). The detector (10) comprises an energy-dispersive X-ray detector element (12) and a means (11) for reducing the amount of the backscattered electrons compared to the amount of the X-rays, arranged in front of the X-ray detector element (12). The means (11) is designed in such a way that the amount of the backscattered electrons (5) compared to the amount of the X-rays (7) is reduced in such a way that the characteristic peaks of the X-rays (7) can be proven compared to the measuring signal of the backscattered electron amount (5), and simultaneously a backscatter electron amount can be proven after the theoretical X-ray bremsstrahlung background is deducted from the measured spectrum.