Precision 3D Printed Nozzles to Reduce X-ray Background and to Improve Efficiency in Single Particle Imaging

Imaging single particles using Free Electron Lasers can profoundly advance our under-standing of chemical and biological processes. Electrospray injection is a promising single particle sample delivery approach used at the SPB (Single Particles and Biomolecules) and SQS (Small Quantum Systems) end stations at EuXFEL. We aim to overcome two main challenges to single particle electrospray injection by optimizing electrospray nozzles using photon stereolithography precision 3D printing. (1) To reduce background noise from injector gas flow, we seek to replace nitrogen gas in the Taylor cone chamber with helium. Its smaller atom cross-section reduces X-ray scattering, but requires a suitable nozzle tip geometry with a local stream of nitrogen and carbon dioxide to protect the Taylor cone from corona discharge. (2) To improve the single particle hit rate, we explore nozzle-array designs for improved single particle injection densities.