Print this page Geophysical Laboratory on Facebook Geophysical Laboratory on Flickr Click for RSS

High Pressure

High pressure science and technology has been a major thrust area at the Geophysical Laboratory since the founding of the department.  The Laboratory continues to develop and explore the field of extreme environments.

The Geophysical Laboratory has made important advances in the growth of diamond by chemical vapor deposition (CVD).  Methods have been developed to produce single-crystal diamond at low pressure having a broad range of properties. Video- "Growing Synthetic Diamonds"

Researchers studying the Earth's core have found that neither the liquid outer core nor the solid inner core is as dense as would be expected if the core were pure iron. Lighter elements must be present. But which ones? Melted samples are subjected to pressures up to 250,000 atmospheres.

Scientists at the Geophysical Laboratory use the dedicated facilities of the Los Alamos and Oak Ridge National Laboratories for the study of neutron scattering of condensed matter.

 

A broad range of optical spectroscopy techniques are used by scientists at the Geophysical Laboratory studying high-pressure phenomena. These techniques include absorption, reflectivity, and emission spectra over a wide spectral range (240-16,000 nm), infrared absorption spectroscopy, and Raman spectroscopy -- These techniques can be used at combined high pressures and variable temperatures from cryogenic to laser heating conditions.

Scientists run hydrothermal organic chemistry experiments at temperatures ranging from 50 up to 250 °C and at pressures from 2-3 MPa up to 400 MPa.

 

Probing minute samples at ultrahigh pressures requires high-energy beams from synchrotrons such as the Advanced Photon Source (APS) at Argonne National Laboratory. Geophysical Laborator yscientists have remained at the forefront of developing these new analytical tools.

High Pressure News

 

Washington, D.C., 14 April 2015— The cores of terrestrial planets and satellite bodies, including the Moon, all contain large quantities of iron.  New work from the Geophysical Laboratory's Yingwei Fei provides new measurements of iron at lunar core conditions that will help build a direct compositional and velocity model of the Moon’s core in conjunction with limited lunar seismic data.

Washington, D.C., 20 March 2015— A team led by Geophysical Laboratory scientists was able to discover five new forms of silica under extreme pressures at room temperature.

Washington, D.C., 17 November 2014— A team led by the Geophysical Laboratory's Timothy Strobel has synthesized an entirely new form of silicon, one that promises even greater future applications. Although silicon is incredibly common in today's technology, its so-called indirect band gap semiconducting properties prevent it from being considered for next-generation, high-efficiency applications. Strobel's silicon has a quasi-direct band gap that falls within the desired range for solar absorption, something that has never before been achieved.

Washington, D.C., 12 November 2014 —Data have suggested that deep, hot, fluid magma oceans of melted silicates, a major Earth material, may reside above the core-mantle boundary. The Geophysical Laboratory's Alex Goncharov has found, using high-pressure experiments with a proxy material, that the deep Earth materials conduct far less heat under increasing pressure than previously thought.

Presentations

Russell J. Hemley "High-Pressure Geoscience: New Tools and Expanding Outreach", Workshop on Long Range Plans for High Pressure earth Sciences (Tempe, AZ, March 2-4, 2009).

Russell J. Hemley "Hydrogen, SUSSP 2008: High Pressure Physics", Scottish Universities Summer School in Physics No. 63 (Isle of Skye, Scottland, May 26-June 6, 2008).

Russell J. Hemley "New Light on Materials under Extreme Conditions: Synchrotron Radiation and High Pressure", ICTP (Trieste, November, 2006).

Russell J. Hemley "Overview of New Developments and Future Prospects in High Pressure Research ", Minerva School (Ein Guedi, March, 2006).