Abstract

The ultrafast pulses from X-ray free-electron lasers enable X-ray imaging beyond conventional radiation damage limits.Although sufficient dose is deposited to completely destroy the sample, it is nevertheless possible to collect meaningful diffraction patterns from the undamaged sample before it is destroyed.Recent results obtained using the Linac Coherent Light Source (LCLS) free electron laser have demonstrated femtosecond diffraction from sub-micron nanocrystals: clear diffraction is seen to the measured resolution limits and little evidence of X-ray damage is observed. Extending the same techniques using harder X-rays may enable atomic resolution imaging of proteins that cannot be crystallized, opening the door to new avenues of structure determination for new classes of hard to crystallize proteins.