Heidelberg 2015 – wissenschaftliches Programm
SYAD 1.3: Hauptvortrag
Dienstag, 24. März 2015, 12:00–12:30, C/HSW
X-ray Imaging of Ultrafast Dynamics in Single Clusters — •Daniela Rupp — IOAP, Technische Universität Berlin
Extremely bright and ultrashort x-ray pulses from free-electron lasers have initiated new fields of research. One of the pioneering projects is capturing molecular movies, i.e. imaging single molecules and ultrafast molecular processes with atomic resolution in time and space. The most challenging task is to record a scattering image before electronic changes and ionic motion within the molecule blur the pattern. In order to approach this goal, we strive towards a profound understanding of ultrafast radiation damage. Atomic clusters have been successfully used as ideal model systems to study laser-matter interaction. We have recently developed single cluster imaging and simultaneous ion spectroscopy as a novel method delivering unprecedented insight into the FEL-induced ionization and plasma dynamics. Knowing the size of the cluster and the FEL exposure power density from the scattering patterns allows for experiments with extremely well defined initial conditions. In recent measurements at the FLASH-FEL single large xenon clusters were irradiated by intense soft x-ray pulses. The scattering images of the single clusters revealed the ultrafast built-up of an inhomogeneously charged nanoplasma. The ion spectra of the same, size-selected clusters indicate that after the interaction with the pulse, the outermost shells of the cluster blast off while most of the dense cluster plasma recombines to neutral atoms. The results emphasize how this combination of tools is able to address different timescales of a complex process and gain a more complete picture of the dynamics.