Comprehensive characterization of gas dynamic virtual nozzles for x-ray free-electron laser experiments

Area of Science:

• Physical Chemistry
• Materials Science
• Instrumentation

Background:

• Characterizing liquid microjets is crucial for X-ray diffraction (XRD) experiments.
• Existing methods for microjet characterization can be time-consuming and lack automation.

Purpose of the Study:

• To introduce a novel hardware-software system for rapid and automated characterization of liquid microjets.
• To establish quantitative metrics for assessing microjet suitability for XRD.

Main Methods:

• Development of an open-source, Python-based software package for data collection and analysis.
• Systematic investigation of factors influencing jet parameters (speed, length, diameter) including nozzle geometry, gas flow rate, liquid viscosity, and liquid flow rate.
• Introduction of "jet instability" and "jet probability" metrics.

Main Results:

• Demonstrated influence of nozzle geometry, gas flow, liquid viscosity, and flow rate on jet characteristics.
• Identified asymmetric needle-tipped nozzles as significantly improving jet stability and reliability.
• Achieved production of microjets with diameters < 250 nm and speeds > 120 m/s.

Conclusions:

• The developed system enables rapid and automated microjet characterization for XRD.
• The new metrics provide a quantitative basis for nozzle selection in XRD experiments.
• Asymmetric needle-tipped nozzles offer a promising approach for generating stable, high-speed microjets suitable for advanced X-ray applications.