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Sample delivery using injectors is widely used in serial crystallography (SX) and has significantly contributed to the determination of crystal structures at room temperature. However, sophisticated injector nozzle fabrication methods and sample delivery operations have made it difficult for ordinary users to access the SX research. Herein, a simple and easily accessible sample delivery method for SX experiments is introduced, that uses a viscous medium, commercially available syringe and syringe pump. The syringe containing the lysozyme crystals embedded in lipidic cubic phase (LCP) or polyacrylamide (PAM) delivery media was connected to a needle having an inner diameter of 168 µm, after which it was installed on a syringe pump. By driving the syringe pump, the syringe plunger was pushed and the crystal sample was delivered to the X‐ray beam position in a stable manner. Using this system, the room‐temperature crystal structures of lysozyme embedded in LCP and PAM at 1.56 Å and 1.75 Å, respectively, were determined. This straightforward syringe pump‐based sample delivery system can be utilized in SX. [ABSTRACT FROM AUTHOR]

The Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL) is a recently commissioned X-ray free-electron laser (XFEL) facility that provides intense ultrashort X-ray pulses based on the self-amplified spontaneous emission process. The nano-crystallography and coherent imaging (NCI) hutch with forward-scattering geometry is located at the hard X-ray beamline of the PAL-XFEL and provides opportunities to perform serial femtosecond crystallography and coherent X-ray diffraction imaging. To produce intense highdensity XFEL pulses at the interaction positions between the X-rays and various samples, a microfocusing Kirkpatrick--Baez (KB) mirror system that includes an ultra-precision manipulator has been developed. In this paper, the design of a KB mirror system that focuses the hard XFEL beam onto a fixed sample point of the NCI hutch, which is positioned along the hard XFEL beamline, is described. The focusing system produces a two-dimensional focusing beam at approximately 2 mm scale across the 2-11 keV photon energy range. XFEL pulses of 9.7 keVenergy were successfully focused onto an area of size 1.94 mm x 2.08 mm FWHM. [ABSTRACT FROM AUTHOR]