Post-sample aperture for low background diffraction experiments at X-ray free-electron lasers

J Synchrotron Radiat. 2017 Nov 1;24(Pt 6):1296-1298. doi: 10.1107/S1600577517011961. Epub 2017 Oct 16.

Abstract

The success of diffraction experiments from weakly scattering samples strongly depends on achieving an optimal signal-to-noise ratio. This is particularly important in single-particle imaging experiments where diffraction signals are typically very weak and the experiments are often accompanied by significant background scattering. A simple way to tremendously reduce background scattering by placing an aperture downstream of the sample has been developed and its application in a single-particle X-ray imaging experiment at FLASH is demonstrated. Using the concept of a post-sample aperture it was possible to reduce the background scattering levels by two orders of magnitude.

Keywords: X-ray diffraction; aperture; background scattering; coherent diffractive imaging; signal-to-noise ratio; single-particle imaging.