X-ray Diffractometer Monochromator Positioning for Intensity
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Solution Overview
Problem
Conventional X-ray diffractometers experience attenuation of diffracted X-rays due to increased optical path length when a monochromator is placed behind the focal point, leading to reduced intensity at the detector.
Innovation Solution
The monochromator is positioned in front of the focal point, utilizing a multilayer mirror with varying interplanar spacing to reflect specific wavelengths without increasing the optical path length, and a two-dimensional X-ray detector with adjustable detection functions is used to enhance measurement flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the monochromator is arranged behind the focal point to monochromate diffracted X-rays, then the detection precision is improved, but the optical path length is increased causing attenuation of X-ray intensity
Solution Approach 1:
The patent inverts the conventional arrangement by placing the monochromator in front of the focal point rather than behind it. This reversal allows the monochromator to receive divergent X-rays before they converge, monochromate them, and then allow the monochromated X-rays to focus at the detector, thereby maintaining short optical path length while achieving effective monochromation.
Solution Approach 2:
The patent introduces a divergent slit as an intermediary component between the X-ray source and the monochromator. This divergent slit controls the divergence angle of X-rays incident on the monochromator, enabling effective monochromation while maintaining a compact optical path. The divergent slit acts as a mediator that reconciles the conflicting requirements of monochromation efficiency and optical path length.
2Measurement precision
If the monochromator is arranged behind the focal point, then the monochromation function is achieved, but the optical path length increases
Solution Approach 1:
The patent inverts the conventional arrangement by placing the monochromator in front of the focal point rather than behind it. This reversal allows the monochromator to receive divergent X-rays before they converge, monochromate them, and then allow the monochromated X-rays to focus at the detector, thereby maintaining short optical path length while achieving effective monochromation.
Solution Approach 2:
The patent performs monochromation as a preliminary action before the X-rays reach the focal point. By monochromating the X-rays earlier in the optical path, the system eliminates the need for a long optical path after monochromation, thus reducing the overall optical path length while maintaining monochromation accuracy.
3Measurement precision
If the receiving slit is arranged to receive focusing X-rays, then the resolution is adjusted, but the structural complexity increases
Solution Approach 1:
The patent designs the receiving slit to serve multiple functions: it receives both focusing and divergent X-rays, adjusts resolution, and works effectively in both operational modes of the diffractometer. This multi-functionality reduces the need for separate components for different functions, thereby simplifying the overall structure while maintaining resolution adjustment capability.
Solution Approach 2:
The patent employs a movable receiving slit that can dynamically adjust its position and opening angle according to the operational mode (focusing or divergent X-rays). This dynamic adjustment allows the receiving slit to optimize resolution for different modes without requiring separate fixed structures, thereby reducing structural complexity while maintaining measurement precision.
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 effective monochromation of X-rays without lengthening the optical path, maintaining X-ray intensity and enhancing detection precision and flexibility in measurement modes.
Implementation Method 1
a reflection type monochromator formed by a planar Goebel mirror for receiving focusing X-rays diffracted from a sample and reflecting only focusing X-rays having a specific wavelength based an a Bragg's condition
Implementation Method 2
the surface of a sample S disposed on a sample stage is irradiated with X-rays generated in an X-ray source 10, and X-rays diffracted from the sample S are detected by an X-ray detector 20
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Only X-rays having a specific wavelength out of focusing X-rays 2 diffracted from a sample S is reflected from a monochromator 60 based on a Bragg's condition, passed through a receiving slit 30 and detected by an X-ray detector 20. The monochromator 60 is configured to be freely removable, and arranged between the sample S and a focal point 2a at which the focusing X-rays 2 diffracted from the sample S are directly focused. At this time, the monochromator 60 is approached to the focal point 2a as closely as possible. The monochromator 60 comprises a multilayer mirror having an internal interplanar spacing which varies continuously from one end to the other end.