Enhancing electrospray ionization efficiency for particle transmission through an aerodynamic lens stack.

Area of Science:

• X-ray science
• Particle physics
• Instrument development

Background:

• The electrospray aerosol generator is crucial for delivering particles in single-particle coherent diffractive imaging (SPI) experiments.
• High particle transmission from solution into the vacuum interaction region is essential for successful SPI experiments.
• Particle transmission efficiency depends on aerosol neutralization and the geometry near the Taylor cone.

Purpose of the Study:

• To investigate and optimize the performance of the electrospray aerosol generator at the European X-ray Free Electron Laser (EuXFEL).
• To determine particle transmission efficiency with different neutralizers and geometries for SPI experiments.
• To identify configurations that maximize particle delivery into the X-ray interaction vacuum chamber.

Main Methods:

• Testing various neutralizers, including vacuum ultraviolet (VUV) and soft X-ray ionizers.
• Evaluating different geometries around the Taylor cone and orifice sizes of the counter electrode.
• Measuring absolute particle transmission values under conditions suitable for SPI.

Main Results:

• A VUV ionizer achieved approximately seven times greater particle transmission efficiency compared to the previously used soft X-ray ionizer.
• Optimizing the orifice size on the counter electrode further enhanced transmission.
• Achieved over 40% particle transmission from solution into the X-ray interaction region.

Conclusions:

• The VUV ionizer is a superior method for neutralizing charged aerosols in electrospray aerosol generators for SPI.
• Optimized generator configurations, including VUV ionization and specific geometries, significantly improve particle transmission.
• These findings provide critical insights for enhancing electrospray aerosol generator setups and increasing data rates for EuXFEL SPI experiments.