Cryogenic coherent X-ray diffraction imaging of biological samples at SACLA: a correlative approach with cryo-electron and light microscopy

Takayama, Y.; Yonekura, K.

doi:10.1107/S2053273315023980

Figure 6
Enhancement of diffraction signals from holey silicon nitride membrane by interfering with signals from CG particles. (a) Electron micrograph of a cluster of CG particles on holey silicon nitride membrane. (b), (e) Diffraction patterns from the holey membrane alone (b) and CG particles on the holey membrane (e). The inset in (b) corresponds to an enlarged view of the central diffraction pattern within $[| {{S_{x,y}}} | \le 6]$ µm⁻¹ showing concentric rings characteristic of the hole. Arrows in (e) indicate characteristic interference fringes extending to the edge of the pattern. (c), (f) Histograms of diffraction intensity and of maximum resolution of the patterns from the holey membrane alone (c) and CG particles on the holey membrane (f). Collected from 578 (c) and 788 XFEL shots (f). Arrows in the histograms in (c) and (f) indicate the intensity and maximum resolution for the corresponding diffraction patterns in (b) and (e), respectively. See also the caption of Fig. 3

for the histograms. (d), (g) Patterson maps calculated from the patterns in (b) and (e), respectively. To minimize the effect from the missing data near the beam center, a 1 − Gaussian high-pass filter was multiplied with the diffraction patterns (Chapman et al., 2006

). Autocorrelation with the hole reveals a twofold larger ring in the Patterson map (d). Cross-correlation or convolution of projected densities of the hole and the CG particles yields a pair of holographic images of the hole (arrows). The bar in (a) represents 500 nm. The color scale in (b) and (e) is identical and shown at the left side of (e). Note that the color scale in (g) is three times higher than that in (d) owing to the high projected electron density of the CG particles.

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ISSN: 2053-2733

Volume 72| Part 2| March 2016| Pages 179-189

https://doi.org/10.1107/S2053273315023980

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