2D X-ray Detector Virtual Scanning for Uniform Exposure
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Solution Overview
Problem
Existing X-ray diffraction systems face challenges in maintaining uniform exposure time across the entire scanning range, particularly when detector scanning range is limited by physical obstacles, leading to incomplete data collection and inaccurate diffraction patterns.
Innovation Solution
A method and apparatus that utilize a two-dimensional X-ray detector to progressively change the portion of the detector contributing to the representation of detected X-ray energy at the extremes of the scanning range, allowing for uniform exposure time through virtual scanning, which simulates additional scanning range without physical under-travel or over-travel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the detector scanning range is extended to cover the entire desired 2θ range, then the angular coverage is improved, but the exposure time uniformity deteriorates due to physical obstacles limiting the scanning range
Solution Approach 1:
The detector's pixel array is divided into multiple segments or regions. Different pixel segments are activated at different scanning positions to compensate for the limited physical scanning range. This segmentation allows the system to simulate a larger scanning range while maintaining uniform exposure time across all 2θ angles by appropriately selecting and weighting contributions from different pixel segments.
Solution Approach 2:
The system dynamically changes the effective detector position and active pixel regions as a function of the scanning angle. By adjusting which pixels are active and how their signals are weighted, the system compensates for the limited physical scanning range and maintains uniform exposure time across the entire desired 2θ range, effectively decoupling the physical scanning range from the logical detection range.
2Reliability
If physical blocks are used to prevent under-travel or over-travel of the detector, then the device reliability is improved, but the angular coverage deteriorates due to limited scanning range
Solution Approach 1:
The system transitions from a one-dimensional physical scanning space to a two-dimensional data space by utilizing the full pixel array of the detector. Different spatial regions of the detector are activated at different scanning positions, effectively adding a spatial dimension to the data collection. This allows the system to achieve extended angular coverage without requiring the physical detector to travel beyond the blocks, maintaining reliability while expanding coverage.
Solution Approach 2:
The system creates a virtual representation of the diffraction pattern by combining data from multiple physical detector positions. By appropriately weighting and combining signals from different pixel regions at different scanning angles, the system synthesizes a complete diffraction pattern that would require a larger physical scanning range, effectively copying the function of a larger scanning system within the constrained physical space.
3Device complexity
If the detector maintains position at extreme scanning points, then the device complexity is reduced, but the exposure time uniformity deteriorates
Solution Approach 1:
The system dynamically adjusts the effective detector configuration by changing which pixel regions are active and how their signals are weighted, based on the current scanning position. This dynamic reconfiguration compensates for the limited physical scanning range and maintains uniform exposure time across all 2θ angles, achieving uniformity without requiring complex mechanical adjustments to the detector position or movement.
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 approach ensures homogeneous exposure time and accurate diffraction data collection across the desired 2θ range, even in constrained spaces, by actively collecting and normalizing X-ray intensities, thereby improving the precision and reliability of X-ray diffraction measurements.
Implementation Method 1
When the angle of incidence, θ, relative to the crystalline structure satisfies the Bragg equation, A=2dsin0, an interferometrically reinforced signal (the diffracted signal), may be observed leaving the material
Implementation Method 2
the detector is moved in an angular direction along a scanning path about a location of the sample while detecting the diffracted X-ray energy
Implementation Method 3
the position of the detector is maintained while the system progressively changes, along said angular direction, the portion of the detector that is used to contribute to the stored representation of the detected X-ray energy
Data Source
Figure 1A~1B
Figure 2~3
Figure 4
AI summary
A method and apparatus for performing an X-ray diffraction measurement with a diffractometer having an X-ray beam directed at a sample and a two-dimensional X-ray detector includes the performance of a physical scan during which the detector is moved through a scanning range in an angular direction about the sample position. To provide a uniform exposure time, the detector, when located at an extreme of the scanning range, is controlled to progressively change the portion of the detected X-ray energy that is used at a rate that maintains a uniform exposure time for each angular position in the scanning range. Alternatively, when located at an extreme of the range, the detector is kept stationary until a desired minimum exposure time is obtained for each angular position, after which the collected diffraction data is normalized relative to exposure time.