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Efree

Malcolm Guthrie

EFree Chief Scientist, GL, CIW

Hydrogen at High P-T Conditions

Study of the phase diagram of hydrogen above one megabar using modified anvil designs with enhanced chemical resistance (with C.S. Zha). An Excimer laser is used to cut dishes into the culets of the diamond anvils, which will then partly be filled with a material that reduces the chemical/physical interaction between hydrogen and diamond.

 

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Extreme P-T Devices

The development of novel instruments is key for the planned research at extreme pressure and temperature conditions at the EFree Center. New diamond pressure cells will expand existing experimental capabilties in the areas of neutron diffraction, synchrotron X-ray measurements, Brillouin spectroscopy, and melting using laser-heating. A challenging task for neutron diffraction to study hydrogen-dominated liquids at megabar pressures and Brillouin spectroscopy for improved melting studies is a significant increase in the sample size.

 

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Synchrotron Radiation

With high brilliance, focusing capabilities, temporal resolution, coherence, and polarization, synchrotron x-radiation is a particularly powerful probe for revealing rich materials behavior under extreme environments. Besides the traditional crystal structure information, recently developed synchrotron techniques provide information on phonon dynamics, electronic and bonding structure, magnetism, micro-structure in a large length scale, nano-imaging, strength and elasticity, and kinetics/process evolution.

 

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EFree Neutron Science

The national neutron facilities are vital to the core science of the EFree Center. Of particular importance is neutron diffraction, with its unique advantages for characterizing new materials. Unlike x-rays, neutrons are sensitive to the positions of light elements in the vicinity of heavy neighbours, and are also often able to resolve adjacent atoms with similar masses. Furthermore, neutrons are scattered by the nuclei of atoms and, thus, are sensitive to subtle displacements and molecular disorder that are hard to detect with x-rays techniques. This same characteristic also lends itself to structural studies of liquids, glasses, and nano-crystalline materials, which remain challenging even with synchrotron x-ray sources.

SNS Spallation Neutron Source

 

 

 

 

 

 

 

EFree has partnerships with facilities at LANSCE (Los Alamos, NM), SNS and HFIR (Oak Ridge, TN).

The central goal of the EFree Neutron Task Force is to achieve new science in the field of novel materials and properties under extreme conditions. The expertise of Carnegie personnel and partners will be exploited to facilitate the technical developments needed to achieve this goal.

 

Personnel

 

Efree Staff

Malcolm Guthrie (Coordinator)
Xiao-Jia Chen (Neutron Scentist)

Key Partners

Chris Tulk, Spallation Neutron Source (SNS)
Yusheng Zhao, Los Alamos Neutron Science Center (LANSCE)
W. Mao, Stanford University
 

Key Projects

 

 

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