High current table-top setup for femtosecond gas electron diffraction.

Area of Science:

• Physical Chemistry
• Molecular Dynamics
• Spectroscopy

Background:

• Gas phase electron diffraction (GED) is crucial for molecular structure determination.
• Achieving femtosecond resolution in GED while maintaining high beam current has been a significant challenge.
• Electron pulse broadening due to Coulomb forces and temporal blurring from velocity mismatch limit current GED capabilities.

Purpose of the Study:

• To construct an experimental setup for gas phase electron diffraction with femtosecond resolution and high average beam current.
• To overcome the limitations of pulse broadening and temporal blurring in ultrafast electron diffraction.

Main Methods:

• Utilized pulse compression techniques to counteract Coulomb broadening of electron pulses.
• Employed laser pulses with a tilted intensity front to compensate for velocity mismatch between laser and electron pulses.
• Characterized temporal resolution using a streak camera.

Main Results:

• Achieved femtosecond temporal resolution (<400 fs) for electron pulses containing up to 500,000 electrons at 90 keV.
• The setup delivers an average beam current 1-2 orders of magnitude higher than previously reported.
• Successfully delivered femtosecond electron pulses onto a gas target.

Conclusions:

• The developed experimental setup overcomes key challenges in ultrafast electron diffraction.
• The high beam current and femtosecond resolution pave the way for advanced studies of molecular structures and dynamics.
• This advancement significantly enhances the capabilities of gas electron diffraction for structural analysis.