Cryptotomography: reconstructing 3D Fourier intensities from randomly oriented single-shot diffraction patterns.

Area of Science:

• Coherent X-ray scattering
• Nanoparticle characterization
• Diffractive imaging

Background:

• Accurate 3D structural determination of nanoparticles is crucial for materials science.
• Current methods often require multiple measurements or specific sample orientations.
• Ultrafast X-ray sources offer potential for single-particle imaging but face challenges with data quality.

Purpose of the Study:

• To demonstrate the feasibility of cryptotomography for reconstructing 3D nanoparticle structures from single-shot diffraction patterns.
• To extend existing computational frameworks to handle experimental data imperfections.
• To advance the potential for single-molecule imaging using ultrafast X-ray sources.

Main Methods:

• Utilized single-shot 2D coherent diffraction patterns from monodisperse prolate nanoparticles.
• Collected data using ultrafast X-ray pulses at DESY's FLASH facility.
• Applied an extended expansion-maximization-compression framework to reconstruct the 3D Fourier intensity distribution, accounting for photon fluence variations and data loss.

Main Results:

• Successfully reconstructed the 3D Fourier intensity distribution of nanoparticles.
• Demonstrated the first experimental application of cryptotomography for this purpose.
• The framework successfully accommodated unmeasured fluctuations in photon fluence and data loss from scatter or saturation.

Conclusions:

• This work represents a significant step towards single-shot diffraction imaging of single biomolecules.
• Cryptotomography, enhanced by robust computational methods, shows promise for structural analysis of nanoscale objects.
• The methodology paves the way for future studies requiring high-resolution structural information from minimal data.