Goniometer Control for X-ray Diffraction Tilt
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Solution Overview
Problem
Existing X-ray diffractometers face limitations in controlling the tilt of a sample during ϕ axis rotation without a special axis configuration, leading to inaccurate incident angles and restricted measurement capabilities.
Innovation Solution
A control apparatus that uses the goniometer's axes to adjust the ω and χ values independently of the ϕ axis rotation, allowing for precise control of the sample's tilt and maintaining a constant incident angle by driving the goniometer's three or more rotation axes simultaneously, including the ϕ, χ, and ω axes, and utilizing the θs and θd axes for incident and receiving angle control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a special axis configuration (RxRy attachment) is provided to adjust sample inclination, then the incident angle control accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the inclination adjustment function from a separate RxRy attachment and integrates it into the goniometer's existing ω and χ axes. By mathematically decoupling the inclination adjustment from the φ rotation, the system achieves the same measurement precision without requiring additional mechanical components, thus resolving the contradiction between precision and complexity.
Solution Approach 2:
The goniometer's ω and χ axes are made multi-functional by enabling them to perform both their traditional functions and the inclination adjustment function previously requiring a separate RxRy attachment. This universalization allows the existing structure to handle multiple measurement tasks without adding dedicated components for each function.
2Adaptability or versatility
If the sample is rotated by φ axis during measurement, then the measurement coverage is improved, but the incident angle accuracy deteriorates due to precession
Solution Approach 1:
The patent implements a feedback mechanism where the control apparatus continuously monitors the φ rotation angle and dynamically adjusts the ω and χ values to compensate for precession effects. This real-time feedback ensures that the incident angle remains accurate throughout the φ rotation range, maintaining both measurement coverage and precision simultaneously.
Solution Approach 2:
The system transitions from static inclination adjustment to dynamic adjustment during φ rotation. The ω and χ values are not fixed but are continuously modified based on the φ angle to maintain constant incident angle geometry. This dynamic approach allows the system to adapt to changing orientations while preserving measurement accuracy.
3Stability of the object's composition
If the crystal axis is matched to φ axis in advance to maintain constant incident angle, then the incident angle stability is improved, but the ease of operation deteriorates due to complex pre-adjustment
Solution Approach 1:
The patent performs preliminary calculation of the required ω and χ adjustment values based on the sample's crystallographic orientation and the desired φ rotation path. By pre-calculating the compensation values and storing them in lookup tables or as mathematical models, the system eliminates the need for manual pre-adjustment operations during actual measurement, thus improving ease of operation while maintaining angle stability.
Solution Approach 2:
The control apparatus automatically performs the inclination adjustment without requiring manual intervention to align crystal axes with the φ axis. The system self-regulates by computing and applying the necessary ω and χ corrections based on input parameters, making the process autonomous and easier to operate while ensuring stable incident angle geometry.
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 accurate control of the incident angle during ϕ axis rotation without the need for a special axis configuration, allowing for high-accuracy measurements in X-ray diffraction, including in-plane XRD, pole figure, and reciprocal space mapping, without the RxRy attachment.
Implementation Method 1
the in-plane rotation of a sample, that is, the rotation of the sample by a φ axis is necessary in each of the in-plane XRD measurement and the reciprocal space mapping
Implementation Method 2
adjustment amounts of a ω value and a χ value for correcting a deviation amount between a scattering vector and a normal line to a sample surface or a lattice plane normal with respect to a φ value that varies
Implementation Method 3
it is necessary to accurately control an incident angle of X-ray. When a sample thickness is thin, a diffraction signal intensity thereof becomes very weak
Implementation Method 4
irradiation of X-rays incident on a surface efficiently becomes necessary according to the in-plane XRD measurement
Data Source
AI summary
There is provided a control apparatus 40 that controls a tilt of a sample, the control apparatus comprising an input section 41 that receives an input of inclination information representing inclination of the sample with respect to a ϕ axis; an adjustment amount determination section 43 that determines adjustment amounts of a ω value and a χ value for correcting a deviation amount between a scattering vector and a normal line to a sample surface or a lattice plane with respect to a ϕ value that varies, using the inclination information; and a drive instruction section 47 that drives a goniometer according to ϕ axis rotation of the sample, based on the determined adjustment amounts of the ω value and the χ value, during an X-ray diffraction measurement.