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Suppression of Emittance Growth Using a Shaped Cold Atom Electron and Ion Source
D J Thompson1, D Murphy1, R W Speirs1
1School of Physics, The University of Melbourne, Victoria 3010, Australia.
Physical Review Letters
|November 19, 2016
Summary
Precise shaping of ultracold charged particle bunches using a cold atom source allows for reversible Coulomb expansion. This technique reduces emittance growth, enhancing focusability and brightness for ultrafast electron diffraction applications.
Area of Science:
- Physics
- Materials Science
- Chemistry
Background:
- Space-charge effects in charged particle beams can limit performance.
- Thermal diffusion typically obscures detailed observation of these effects.
- Controlling particle bunch shape is crucial for advanced applications.
Purpose of the Study:
- To demonstrate precise control over charged particle bunch shape.
- To investigate the impact of 3D bunch shaping on Coulomb expansion and emittance growth.
- To improve the focusability and brightness of particle sources for ultrafast electron diffraction.
Main Methods:
- Utilizing a cold atom electron and ion source.
- Creating charged particle bunches with linear, reversible Coulomb expansion.
- Employing ultracold charged particles to minimize thermal diffusion effects.
Main Results:
- Achieved precise 3D control of charged particle bunch shape.
- Demonstrated a marked reduction in Coulomb-driven emittance growth.
- Observed increased bunch focusability and brightness.
Conclusions:
- 3D shaping of ultracold charged particle bunches effectively suppresses emittance growth.
- The developed technique enables sources for coherent single-shot ultrafast electron diffraction.
- Applications span femtosecond chemistry, materials science, and drug design.
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