Synchronized droplet nozzle for in-vacuum X-ray scattering experiments

Area of Science:

• Physics
• Materials Science
• Chemical Physics

Background:

• Liquid microjets are crucial for sample delivery in X-ray Free Electron Laser (XFEL) experiments.
• Continuous jets lead to significant sample waste, especially for precious or difficult-to-produce samples.
• Improved sample delivery efficiency is needed to optimize XFEL experimental throughput.

Purpose of the Study:

• To develop a novel droplet generation system for efficient sample delivery at XFELs.
• To achieve precise synchronization of liquid microdroplets with external triggers.
• To minimize sample waste and enhance experimental efficiency.

Main Methods:

• Development of 3D-printed gas dynamic virtual nozzles (GDVN).
• Demonstration of 1 kHz droplet ejection synchronized via piezoelectric transduction.
• Utilizing a co-flowing helium sheath gas for vacuum ejection or atmospheric operation.
• Implementation of a control system for enhanced synchronization accuracy.

Main Results:

• Successful generation of periodic liquid microdroplets synchronized with a 1 kHz trigger.
• Achieved synchronization where 60% of droplet positions were within 25% of the droplet diameter.
• Demonstrated operation in vacuum (minimizing X-ray scatter) and at atmospheric pressure.
• Numerical simulations validated experimental data, revealing meniscus recirculation and synchronization dynamics.

Conclusions:

• 3D-printed GDVN offers an efficient method for synchronized microdroplet generation.
• The system significantly improves sample delivery efficiency for XFEL applications.
• The technology is adaptable for minimal modification at existing XFEL and synchrotron end-stations.