Protocol using similarity score and improved shrink-wrap algorithm for better convergence of phase-retrieval calculation in X-ray diffraction imaging

Yoshida, S.; Harada, K.; Uezu, S.; Takayama, Y.; Nakasako, M.

doi:10.1107/S1600577523009864

Figure 1
(a) Single-shot diffraction pattern from an aggregate of ten colloidal gold particles recorded using an XFEL pulse. The pattern displayed good centro-symmetry. (b) Progress of 840 PR calculations with the ordinary protocol (details are given in Section 3.5

) for the diffraction pattern in panel (a). The position of each PR map (red dot) is plotted on the plane spanned by the first and second PC vectors (PC1 and PC2) obtained using PCA for the final 840 maps after the 10000 PR calculations (details are given in Section 3.8

). The gray-scaled background map commonly shown in each panel displays how frequently PR maps visited each position on the plane during the 840 PR calculations. The scale of the frequency is presented at the top of the panel, and the number of PR cycles is labeled in the upper left of each panel. The green circle indicates the area of the 840 random maps for initiating independently three sets of 280 PR calculations. The PR maps in the three regions designated α, β and γ, where PR maps frequently resided, are depicted with a scale bar of 500 nm. Realistic maps from 52.6% of all the trial PR calculations appeared in region α only and yielded similarity scores smaller than 0.2. The diffraction pattern in our previous work (Sekiguchi et al., 2017

) was used with approval from the International Union of Crystallography.

JOURNAL OF
SYNCHROTRON
RADIATION

ISSN: 1600-5775

Volume 31| Part 1| January 2024| Pages 113-128

https://doi.org/10.1107/S1600577523009864

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