|
X-ray scattering is an approved method for structure analysis of matter. With super-intense, ultrashort laser pulses from free-electron lasers with wavelengths of currently 13.5 nm at the FLASH FEL and a few Angstrom for atomic resolution at the planned X-FEL, imaging of nano structures with single-shot scattering experiments becomes possible. We have performed single-shot scattering experiments on single Xenon clusters with diameters comparable to the wavelength (20 to 150 nm). For that purpose a new experimental setup and a detector unit have been developed, containing novel pnCCD detectors and a beamguide based on multilayer mirrors. The obtained scattering data is compared to simulations based on Mie theory. For these calculations the free variables are the size parameter describing the ratio of cluster size and wavelength as well as the complex refractive index. Thus, the size of the imaged clusters could be identified. Further, the refractive index was adjusted to the data. As the refractive index is correlated to the ionization level of the cluster plasma, the experiments yield insight into the ultrafast electron dynamics during femtosecond X-ray pulses. |
|