Particle Beam X-ray Detector Membrane Transmittance
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Solution Overview
Problem
Conventional electron microscopes with X-ray detectors have low detection efficiency, particularly when the primary electron beam has low energy, and magnetic electron traps can disrupt the focusing of the primary electron beam, reducing system performance.
Innovation Solution
A particle beam system with an X-ray detector comprising multiple semiconductor detectors, each with a membrane of varying transmittance for secondary electrons, allowing for accurate detection of X-rays without magnetic traps, and an actuator to selectively position membranes for varying detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic electron traps are used in the X-ray detector to prevent secondary electron detection, then electron detection interference is reduced, but the electromagnetic fields generated by the objective lens are disturbed, affecting primary electron beam focusing
Solution Approach 1:
The patent removes magnetic electron traps from the X-ray detector system entirely. Instead, it uses membranes with different secondary electron transmittances in front of semiconductor detectors to distinguish X-ray signals from electron signals, thereby eliminating the harmful electromagnetic interference while maintaining X-ray detection accuracy.
Solution Approach 2:
The patent introduces membranes as intermediary elements between the object and semiconductor detectors. These membranes have different transmittances for secondary electrons, allowing them to act as selective filters that permit X-rays to pass through while modulating electron signals, thus eliminating the need for magnetic traps.
2Device complexity
If conventional X-ray detectors are used without selective electron blocking, then the detector configuration is simple, but secondary electrons generate erroneous detection signals that cannot be distinguished from X-ray signals
Solution Approach 1:
The patent divides the detection function into multiple semiconductor detectors, each equipped with membranes having different secondary electron transmittances. By segmenting the detection system and using membranes with varying electron transmission properties, the system can distinguish X-ray signals from electron signals through comparative analysis of detection events across multiple detectors.
Solution Approach 2:
The patent applies membranes with different local properties (different secondary electron transmittances) in front of different semiconductor detectors. This local differentiation in membrane characteristics enables each detector to have a distinct response to electron signals, allowing for signal discrimination while maintaining overall system simplicity.
3Use of energy by moving object
If the primary electron beam has low energy, then the system operates with lower power, but X-ray detection efficiency becomes too low
Solution Approach 1:
The patent employs a feedback mechanism where detection events from multiple semiconductor detectors with different membrane transmittances are compared and analyzed. This feedback loop allows the system to distinguish X-ray signals from electron signals even at low beam energies, thereby maintaining X-ray detection efficiency without requiring high primary electron beam energy.
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
Improves X-ray detection accuracy by distinguishing between X-ray and electron detection events, enhancing the overall performance of the particle beam system by avoiding magnetic trap interference with electromagnetic fields.
Implementation Method 1
a membrane or window is located between the object and the detection surface of the respective detector. The membranes located in front of the at least two semiconductor detectors differ with respect to a transmittance for secondary electrons
Implementation Method 2
an X-ray detector having at least two semiconductor detectors, wherein each of the semiconductor detectors has a detection surface oriented towards an object disposed in the object plane for inspection
Data Source
Figure 1
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AI summary
A particle beam system comprises a particle beam source 5 for generating a primary particle beam 13, an objective lens 19 for focusing the primary particle beam 13 in an object plane 23; a particle detector 17; and an X-ray detector 47 arranged between the objective lens and the object plane. The X-ray detector comprises plural semiconductor detectors, each having a detection surface 51 oriented towards the object plane. A membrane is disposed between the object plane and the detection surface of the semiconductor detector, wherein different semiconductor detectors have different membranes located in front, the different membranes differing with respect to a secondary electron transmittance.