Ultrafast self-gating Bragg diffraction of exploding nanocrystals in an X-ray laser
Carl Caleman, Nicusor Timneanu, Andrew V Martin, H Olof Jonsson, Andrew Aquila, Anton Barty, Howard A Scott, Thomas A White, Henry N Chapman
OPTICS EXPRESS | OPTICAL SOC AMER | Published : 2015
In structural determination of crystalline proteins using intense femtosecond X-ray lasers, damage processes lead to loss of structural coherence during the exposure. We use a nonthermal description for the damage dynamics to calculate the ultrafast ionization and the subsequent atomic displacement. These effects degrade the Bragg diffraction on femtosecond time scales and gate the ultrafast imaging. This process is intensity and resolution dependent. At high intensities the signal is gated by the ionization affecting low resolution information first. At lower intensities, atomic displacement dominates the loss of coherence affecting high-resolution information. We find that pulse length is ..View full abstract
The authors thank the Helmholtz Association through the Center for Free-Electron Laser Science at DESY, Swedish Research foundation, Rontgen Angstrom Cluster, and the Swedish Foundation for Strategic Research for financial support. The Swedish National Infrastructure for Computing, UPPMAX (project S00111-71 and p2012227) and David van der Spoel are acknowledged for computational resources, and Magnus Bergh for support with CRETIN simulations.