Effect of the coherence properties of self-amplified-spontaneous-emission x-ray free electron lasers on single-particle diffractive imaging.

The longitudinal coherence properties of self-amplified-spontaneous- emission x-ray free electron lasers limit the resolution of single-particle diffraction imaging. We found that for the Linac Coherent Light Source (LCLS) at a wavelength of 1.5 A the particles have to be smaller than 500 nm in diameter to achieve atomic-resolution imaging with a resolution length of less than 2 A, suggesting that the longitudinal coherence is sufficient for imaging most biomolecular samples of interest.