Magnetic Deflector Filter for X-ray Detector Collision Avoidance
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Solution Overview
Problem
In X-ray analysis using electron microscopes, backscattered electrons overwhelm the signal from X-ray photons, and the detector's large size or proximity to the sample can collide with the microscope's pole piece, limiting the collection of X-ray photons effectively.
Innovation Solution
A charged particle filter with a magnetic deflector having a bore that allows charged particles to pass through, formed by two magnets with a gap and curved or slanted surfaces, enabling the detector to be positioned closer to the sample without colliding with the pole piece, thereby increasing the solid angle of detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the sensor is placed closer to the sample to increase the solid angle of detection, then the X-ray photon collection efficiency is improved, but the detector tube collides with the conical pole piece of the electron microscope
Solution Approach 1:
A magnetic deflector is introduced as an intermediary component between the electron microscope and the X-ray detector. This deflector uses magnetic fields to redirect backscattered electrons away from the detector tube, preventing collision with the pole piece while allowing the detector to be positioned closer to the sample for improved X-ray collection efficiency
Solution Approach 2:
The harmful backscattered electrons are extracted or removed from the path between the sample and detector by using the magnetic deflector to redirect them away from the detector tube, eliminating the collision problem while maintaining close detector positioning
2Productivity
If the active area of the X-ray detector is increased to collect more signal, then the solid angle of detection is improved, but the external diameter of the detector tube must be minimized to avoid collision with the pole piece
Solution Approach 1:
The magnetic deflector acts as a protective intermediary that shields the detector tube from backscattered electrons, enabling the use of larger active areas without increasing the external diameter to collision-prone dimensions
3Productivity
If a large aperture is used to increase the solid angle, then more X-ray photons are collected, but the detector tube structure becomes more complex and larger
Solution Approach 1:
The magnetic deflector provides a compact solution for protecting the detector, allowing larger apertures to be implemented without proportionally increasing the overall tube structure complexity or size
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 configuration allows for more effective collection of X-ray photons by minimizing the detector's external diameter and enabling closer proximity to the sample without collision, enhancing the X-ray spectrum measurement.
Implementation Method 1
A charged particle filter includes a magnetic deflector having a bore along an axis thereof passing through the magnetic deflector from a sample end to a detector end of the magnetic deflector
Data Source
AI summary
A charged particle filter includes a magnetic deflector having a bore (220) along an axis thereof passing through the magnetic deflector from a sample end to a detector end of the magnetic deflector, and through which bore charged particles pass when in use, the magnetic deflector being formed from two magnets (250, 260) positioned around the bore, with a gap (270) between the two magnets, the two magnets each having a linear central section (280, 281) and two ends (285, 286, 295, 296), each end forming a curved or slanted surface (at 285, 286, 295, 296), the curved surface having in some embodiments an aspect ratio defined by a height in a range of between one tenth and ten times the gap between the two magnets, and a width in a range of between one tenth and ten times the gap.