Diffractive Imaging

Coherent diffractive imaging at x-ray free-electron lasers (XFELs) promises the imaging and reconstruction of the three-dimensional molecular structure of isolated (biological) molecules and nanoparticles at atomic resolution. However, so far these experiments are limited by low signal-to-noise ratios and, therefore, require the collection of a very large number of diffraction patterns. The ideal sample delivery method for single-particle coherent diffractive imaging experiments delivers exactly one new and preferably identical sample particle into every x-ray pulse. We develop techniques for the control of gas-phase nanoparticles and biomolecules to render such imaging experiments feasible: optimized aerodynamic lens stacks for the generation of focused particle beams, their optimization for a certain particle species and a low-temperature (4 K) buffer-gas cell to rapidly freeze biological nanoparticles to cryogenic temperatures and to produce cold and controlled beams of such samples. Using our simulation framework, we are able to optimize the injector-geometry and experimental parameters to produce the highest density particle beams for a specific sample, especially important when moving to smaller samples like proteins where the the amount of scattering signal and the general transmission of the sample decreases.

Research Team
Lena Worbs, Armando Estillore, Muhamed Amin, Amit Samanta, Jochen Küpper