Towards a quantitative determination of strain in Bragg coherent X-ray diffraction imaging: artefacts and sign convention in reconstructions

Jérôme Carnis (Corresponding author), Lu Gao, Stéphane Labat, Young Yong Kim, Jan Philipp Hofmann, Steven John Leake, Tobias Urs Schülli, Emiel Hensen, Olivier Thomas, Marie-Ingrid Richard

Onderzoeksoutput: Bijdrage aan tijdschriftTijdschriftartikelAcademicpeer review

26 Citaten (Scopus)
109 Downloads (Pure)

Samenvatting

Bragg coherent X-ray diffraction imaging (BCDI) has emerged as a powerful technique to image the local displacement field and strain in nanocrystals, in three dimensions with nanometric spatial resolution. However, BCDI relies on both dataset collection and phase retrieval algorithms that can induce artefacts in the reconstruction. Phase retrieval algorithms are based on the fast Fourier transform (FFT). We demonstrate how to calculate the displacement field inside a nanocrystal from its reconstructed phase depending on the mathematical convention used for the FFT. We use numerical simulations to quantify the influence of experimentally unavoidable detector deficiencies such as blind areas or limited dynamic range as well as post-processing filtering on the reconstruction. We also propose a criterion for the isosurface determination of the object, based on the histogram of the reconstructed modulus. Finally, we study the capability of the phasing algorithm to quantitatively retrieve the surface strain (i.e., the strain of the surface voxels). This work emphasizes many aspects that have been neglected so far in BCDI, which need to be understood for a quantitative analysis of displacement and strain based on this technique. It concludes with the optimization of experimental parameters to improve throughput and to establish BCDI as a reliable 3D nano-imaging technique.
Originele taal-2Engels
Artikelnummer17357
Aantal pagina's13
TijdschriftScientific Reports
Volume9
DOI's
StatusGepubliceerd - 1 dec. 2019

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