  An aerodynamic lens injector was developed specifically for the needs of
single-particle diffractive imaging experiments at free-electron lasers. Its
design allows for quick changes of injector geometries and focusing properties
in order to optimize injection for specific individual samples. Here, we
present results of its first use at the FLASH free-electron-laser facility.
Recorded diffraction patterns of polystyrene spheres are modeled using Mie
scattering, which allowed for the characterization of the particle beam under
diffractive-imaging conditions and yield good agreement with
particle-trajectory simulations.
