Single-shot mega-electronvolt ultrafast electron diffraction for structure dynamic studies of warm dense matter

Area of Science:

• Materials Science
• Condensed Matter Physics
• Plasma Physics

Background:

• Understanding warm dense matter (WDM) is crucial for fields like inertial confinement fusion.
• Characterizing structural dynamics in WDM requires advanced diagnostic techniques.
• Previous methods faced limitations in temporal and spatial resolution for WDM studies.

Purpose of the Study:

• To develop and demonstrate a single-shot mega-electronvolt ultrafast electron diffraction (MeV-UED) system.
• To measure the structural dynamics of warm dense matter with high temporal resolution.
• To investigate the solid-liquid phase transition in laser-excited gold.

Main Methods:

• Utilized a single-shot MeV-UED system with a 3.2 MeV electron probe.
• Employed a 350 fs pulse duration and 20 fC electron charge.
• Analyzed atomic structural changes in a 35-nm freestanding single-crystal gold foil.
• Quantitatively determined Bragg peak intensity and liquid signal evolution.

Main Results:

• Successfully visualized atomic structural changes in warm dense gold.
• Quantified the temporal evolution of structural changes during the solid-liquid phase transition.
• Demonstrated the capability to probe WDM structural dynamics with femtosecond resolution.

Conclusions:

• The developed MeV-UED system provides a powerful tool for studying WDM.
• This technique enables quantitative analysis of structural phase transitions in WDM.
• Opens new avenues for unraveling atomic dynamics in extreme states of matter.