Relativistic electron diffraction at the UCLA Pegasus photoinjector laboratory

Area of Science:

• Materials Science
• Physics
• Chemistry

Background:

• Electron diffraction offers real-time atomic motion insights at lower costs than X-ray sources.
• Current time-resolution limits are dictated by electron pulse duration.
• Space charge effects limit electron beam intensity and pulse duration.

Purpose of the Study:

• To explore MeV-level electron energies to reduce space charge effects.
• To utilize radio-frequency (RF) photoinjectors for ultrafast electron diffraction (UED).
• To achieve sub-100-femtosecond (fs) electron pulses for high time resolution.

Main Methods:

• Employing RF photoinjectors to generate high-intensity, short electron bunches.
• Utilizing relativistic electron beams (MeV level) to mitigate space charge forces.
• Operating the UCLA Pegasus laboratory's advanced photoinjector facility.

Main Results:

• Demonstrated electron diffraction using a relativistic beam from an RF photoinjector.
• Achieved electron beam pulses measured to be sub-100-fs long.
• Obtained diffraction patterns from titanium and aluminum metal targets.

Conclusions:

• RF photoinjector-based UED is a viable technique for studying ultrafast phenomena.
• Future work will focus on optimizing RF photoinjector performance in the low-charge, ultrashort pulse regime.
• Development of specialized beam diagnostics is crucial for advancing this technique.