Circular Phase-Shifting Grating for Omnidirectional X-Ray Scattering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current X-ray grating interferometry systems require time-consuming sample or interferometer rotation for multi-directional scattering sensitivity, and existing setups are complex and sensitive to noise variations, limiting their ability to detect micro-structures uniformly without demanding alignment.
Innovation Solution
A single-shot imaging arrangement with a circular phase-shifting grating and a charge integrating detector provides omnidirectional scattering sensitivity, differential phase contrast in two directions, and absorption contrast without rotation or shifting of optical elements or the sample, using a dedicated phase grating design and optimized detector resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If linear gratings are used for grating interferometry, then the setup is simple, but the scattering sensitivity is limited to only one direction (perpendicular to grating lines)
Solution Approach 1:
The phase grating is divided into multiple linear grating segments arranged in different orientations (e.g., vertical, horizontal, diagonal). Each segment provides scattering sensitivity in its respective direction, collectively achieving omnidirectional coverage without requiring rotation of the entire interferometer or sample.
Solution Approach 2:
Instead of using a single symmetric linear grating with uniform orientation, the patent employs an asymmetric arrangement of multiple grating segments with different orientations. This asymmetric configuration enables multi-directional scattering sensitivity while maintaining a fixed, non-rotating setup.
2Adaptability or versatility
If 2D gratings are used to provide multi-directional scattering sensitivity, then omnidirectional sensitivity is achieved, but the imaging setup becomes complicated requiring raster scanning
Solution Approach 1:
The complex 2D grating is segmented into multiple independent linear grating elements arranged in a fixed pattern. This segmentation eliminates the need for raster scanning while preserving multi-directional sensitivity, as each segment independently contributes to scattering detection in its specific orientation.
Solution Approach 2:
Instead of using a single complex 2D grating that requires scanning, the patent inverts the approach by using multiple simple linear gratings in a fixed array. This inversion simplifies the imaging setup by eliminating the scanning mechanism while achieving the same multi-directional sensitivity goal.
3Adaptability or versatility
If sample or interferometer rotation is performed to obtain multi-directional scattering sensitivity, then scattering sensitivity in multiple directions is achieved, but the acquisition time increases significantly
Solution Approach 1:
The grating segments are pre-arranged in fixed orientations that cover all desired scattering directions. This preliminary configuration eliminates the need for time-consuming rotation operations during acquisition, as the omnidirectional sensitivity is already built into the static grating structure.
Solution Approach 2:
The mechanical rotation system (either rotating the sample or the interferometer) is replaced by a fixed array of gratings with different orientations. This substitution eliminates mechanical movement entirely, enabling fast acquisition without rotation while maintaining multi-directional scattering sensitivity.
4Adaptability or versatility
If membrane scanning is used to sense scattering signal, then scattering sensitivity is achieved, but the setup remains complex and sensitivity is limited to scan direction only
Solution Approach 1:
The single scanning membrane is replaced by multiple fixed grating segments oriented in different directions. Each segment provides scattering sensitivity in its specific orientation without requiring scanning, collectively achieving omnidirectional sensitivity in a static configuration.
Solution Approach 2:
The mechanical scanning mechanism of the membrane is replaced by a fixed grating array. This substitution eliminates the need for scanning motion while providing scattering sensitivity in multiple directions simultaneously, as each grating segment independently detects scattering in its respective orientation.
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 uniform detection of micro-structures with omnidirectional sensitivity, fast acquisition, and straightforward mechanical setup, eliminating the need for sample or optical element rotation, and enhancing spatial resolution for improved imaging capabilities.
Implementation Method 1
the phase-shift periodic structure G1 creates a periodic interference pattern with a repetition of each unit cell P' and the period within each unit cell is p' at a known distance (Talbot effect) downstream on the PSD
Implementation Method 2
a phase-shifting or phase-modulating grating G1 downstream the sample, the phase-shifting grating G1 having a circular shape and comprising a mosaic or honeycomb repetition of circular gratings or unit cells
Implementation Method 3
an X-ray source, in case of a polychromatic X-ray source a source grating may be used
Data Source
Figure 1
Figure 2a~3
Figure 4(a)~4(d)
AI summary
X-ray scattering imaging can provide complementary information about the unresolved microstructures of a sample. The scattering signal can be accessed with various methods based on coherent illumination, which span from self-imaging to speckle scanning. The directional sensitivity of the existing methods is limited to a few directions on the imaging plane and it requires the scanning of the optical components, or the rotation of either the sample or the imaging setup, if the full range of possible scattering directions is desired. The present invention discloses a new arrangement that allows the simultaneous acquisition of the scattering images in all possible directions in a single shot. This is achieved by a specialized phase grating and means of recording the generated interference fringe with sufficient spatial resolution. The proposed technique decouples the sample dark-field signal with the sample orientation, which can be crucial for medical and industrial applications.