III. Coherent Diffraction by Nanostructures

Atomic-resolution structure of biological and inorganic nanostructures with lensless imaging

  • The challenges of bio-imaging
  • Lensless imaging
  • Protein nanocrystals and 2d-crystals
  • Imaging of single biomolecules
  • Space- and time-correlations in coherent scattering
  • Lensless imaging of inorganic nanostructures
The high transverse coherence of the SwissFEL will allow nanostructures such as biomolecular complexes and crystal defects to be imaged at atomic resolution using the technique of lensless imaging. This diffraction technique relies on the solution of the phase problem. Furthermore, the SwissFEL’s high peak brilliance and shor t pulse length offer solutions to the major problems in structural biology: the limited availability of high-quality crystals and the sample degradation through radiation damage. The ability to image single biomolecules with the SwissFEL would bring enormous benefit: of the more than 51'000 structures in the Protein Data Bank, less than 200 are of the difficult to crystallize but biologically vital membrane proteins. In parallel to the challenge of injecting individual nanocrystals or biomolecules into the SwissFEL beam, highly intelligent procedures for the collection and analysis of large numbers of low-statistic coherent speckle patterns must be developed. By combining lensless imaging with a suitable pump source, the SwissFEL will in addition allow the study of the dynamics of nanostructures, both organic and inorganic.