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)

Energy dispersive X-ray diffraction system, X17B.

Symmetric type cell being used in a radial diffraction experiment.

Cornell High Energy Synchrotron Source (CHESS)