Synchrotron x-ray diffraction
To study crystal structures and how they change as a function of pressure
and temperature, we use synchrotron x-ray diffraction facilities all over
the United States. A major focus has been to combine diamond anvil
cell techniques with laser heating (using a high-powered infrared laser)
to simultaneously achieve extremes of pressure and temperature -- up to
300 GPa and 3000 K.
Recent high-pressure x-ray diffraction projects:
- Suki Dorfman: Pyrope-almandine composition perovskites
- Zhu Mao: High-pressure phases of GGG and YIG to Mbar pressures
- Suki Dorfman: Phase transitions and equations of state of alkaline earth fluorides CaF2 and SrF2 to Mbar pressures
- Claire Runge: Equation of state of MgGeO3 perovskite to 65 GPa: comparison with the post-perovskite phase
Synchrotron facilities
Advanced Photon Source (APS)
This is a third-generation synchrotron facility at Argonne National Laboratory.
At the GSECARS sector of the Advanced Photon Source, we are using a new
double-sided laser heating system which can generate very stable heating
conditions at high pressure. Recently we have used this facility
to study MgSiO3 and CaSiO3 perovskite, which are believed to be the major
phases of the Earth's lower mantle, to conditions corresponding to 2000
km depth in the Earth. Also at the APS, we has used radial diffraction
techniques to obtain elasticity tensors from x-ray diffraction data obtained
under non-hydrostatic conditions
Advanced
Photon Source (APS), Argonne National Laboratory.
GSECARS
sector of the Advanced Photon Source.
Energy
dispersive X-ray diffraction system at GSECARS.
Double-sided
laser heating system at GSECARS.
Schematic
illustration showing single-sided and double-sided laser heating techniques.
National Synchrotron Light Source (NSLS)
The NSLS is a second-generation synchrotron source which has facilities
for energy dispersive diffraction (X17C) and laser heating combined with
energy dispersive diffraction (X17B).
Energy
dispersive X-ray diffraction system, X17B.
Symmetric
type cell being used in a radial diffraction experiment.
Cornell High Energy Synchrotron Source (CHESS)
At CHESS, we perform high-resolution diffraction experiments in an angle
dispersive geometry and using an imaging plate (area) detector.
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