More than a decade ago:
Accelerator development enabled visionary science
probe-before-destroy
Haidu et al.
soft x-ray magnetic
holography
Wang, et al. PRL (2013)
Today: We need the complementarity of x-rays & electrons
to access to the “Ultrafast” & “Ultrasmall”
Goal: understand & control
materials processes
FePt
heat sink
probes electrons
& spins
probes lattice
G. Bertero (WD Corp.)
soft x-ray magnetic
holography
Wang, et al. PRL (2013)
nano-UED
Xiang, et al. SLAC report
(2014)
X-rays or electrons? We need both!
Electrons:
can be manipulated by electric &
magnetic fields (microscopy) but have
<10nm coherence lengths.
X-rays:
Fully coherent beams offer new
opportunities for holographic imaging.
Soft x-ray resonant inelastic cross
sections are comparable to those of
electrons, elastic cross sections are
much lower.
R. Henderson, Quarterly Reviews of Biophysics 28 (1995) 171-193.
The Future of Electron Scattering & Diffraction
Opportunities for Ultrafast Science
Key Breakthrough Science Opportunities and Challenges
- Atomic Scale Molecular Processes
- Photonic Control of Quantum Materials
- Energy Transport at the Nanoscale
- Mesoscale Materials and Phenomena
- Evolving Interfaces, Nucleation, and Mass Transport
DOE Basic Energy Sciences Needs
Workshop Report (2014)
The Future of Electron Scattering & Diffraction
How do we get there?
UEM
User Facility
Nano-UED
User Facility
Ultrafast
Electron Diffraction
Ultrafast
Electron
Microscopy
DOE Basic Energy Sciences Needs
Workshop Report (2014)
Ben-Nun and Martinez, Chem. Phys. 259, 237(2000)
Controlling processes on the level of electrons:
Non-Born-Oppenheimer dynamics in molecules
•requires sub-100 fs with
unfocused electron beam
at high repetition rates
(UED)
• Absorption triggers coupled ultrafast motion of
nuclei and electrons, hard to model
• Born-Oppenheimer violation provides fast funnels
for steering energy into particular channel
M. Centurion Lab
U. Nebraska
Aligned CF3I
Guehr, et al.
Opportunities for Ultrafast Materials Science
• nanoscale energy transport
•requires sub-100 fs with
focused electron beam at
high repetition rates
(nano-UED)
• photonic control of
quantum materials
• nanoscale mechanisms
of phase transitions
Imaging of Nanoscale Processes
• Phase transitions: diffusionless
vs. mass transport
•requires single-shot
imaging
(10ps - 10 nm UEM)
• Biological processes
Carbon fixation by bacterial carboxysomes
Early Science Opportunities with UED
UEM
User Facility
Nano-UED
User Facility
Ultrafast
Electron Diffraction
Ultrafast
Electron
Microscopy
Gas phase chemistry (sub-100fs &
100μm beam size): Experimental
setup is still under development
(requires isolation of gun and
sample vacuum).
Materials science will initially be
limited by available samples:
etching, exfoliation, sample growth
of ~ 100μm free standing films
needs to be developed)
Development of laser-electron
cross correlation schemes:
- use laser-induced space charge
- electron beam induced dynamics
- photo-induced electron-lattice
coupling in wide-bandgap oxides
Early Science Opportunities with UED
First results (A. Reid, R. Li, P. Musumeci)
Gas phase chemistry (sub-100fs &
100μm beam size): Experimental
setup is still under development
(requires isolation of gun and
sample vacuum).
Materials science will initially be
limited by available samples:
etching, exfoliation, sample growth
of ~ 100μm free standing films
needs to be developed)
Measurement of single-shot electron diffraction from a
40nm FeRh film epitaxially grown on 10 nm MgO IBAD
deposited on 100nm SiN.
Development of laser-electron
cross correlation schemes:
- use laser-induced space charge
- electron beam induced dynamics
- photo-induced electron-lattice
coupling in wide-bandgap oxides