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Measurement of X-ray Beam Coherence along Multiple Directions Using 2-D Checkerboard Phase Grating
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Impact and mitigation of angular uncertainties in Bragg coherent x-ray diffraction imaging
I Calvo-Almazán1, M Allain2, S Maddali3
1Materials Science Division, Argonne National Laboratory, Argonne, Illinois, 60439, USA. ialmazn@anl.gov.
Scientific Reports
|April 24, 2019
Summary
Angular uncertainty in Bragg coherent diffraction imaging (BCDI) can degrade crystal morphology and strain analysis. This study introduces a novel phase retrieval algorithm to simultaneously reconstruct objects and determine precise angular positions, mitigating artifacts for improved nanoscale imaging.
Area of Science:
- Materials Science
- Crystallography
- Coherent X-ray Optics
Background:
- Bragg coherent diffraction imaging (BCDI) offers high-resolution analysis of microscale crystal strain and morphology.
- Advancements in synchrotron sources enable nanometer-scale resolution, but experimental limitations persist.
- Sample angular uncertainty is a key bottleneck affecting image reconstruction quality in BCDI.
Purpose of the Study:
- To identify and address experimental bottlenecks in Bragg coherent diffraction imaging.
- To develop a method for mitigating artifacts caused by sample angular uncertainty.
- To improve the accuracy of nanoscale imaging and analysis in BCDI.
Main Methods:
- An alternative formulation of the forward problem in BCDI was developed.
- A novel phase retrieval algorithm was designed for simultaneous object reconstruction and angular position determination.
- Algorithm performance was evaluated using simulated data with varying angular uncertainty and signal-to-noise ratios.
Main Results:
- The proposed algorithm effectively mitigates artifacts arising from sample angular uncertainty.
- Simultaneous reconstruction of the object and determination of angular positions were achieved.
- The method demonstrates robustness across different levels of angular uncertainty and noise.
Conclusions:
- Sample angular uncertainty is a critical factor impacting BCDI image quality.
- The developed phase retrieval algorithm successfully addresses this limitation.
- This approach enhances the reliability and resolution of nanoscale crystal characterization using BCDI.
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