Development of Laser Heating for Sound Velocity Measurements at High P and T

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

0002021 Bass This award supports the development of instrumentation and techniques to enable the measurement of acoustic wave velocities in minerals and other solids at extremely high pressures and temperatures that are characteristic of the Earth's deep interior. The technique will couple the laser heated diamond anvil cell with Brillouin spectroscopy. Development of this technology will yield direct information on the seismic velocities in materials under conditions that have never before been attained. Experiments will be obtained on materials that are thought to be constituents of the Earth's deep interior, and the results will be compared with information on the velocity structure of the Earth as obtained from seismological studies. Results should yield significant new insights on the chemical composition of the Earth at depth, the thermal structure of the Earth, and Earth's evolution through time. The facility will allow measurement of the physical properties of a variety of solid materials (not just minerals) under extreme temperature and pressure conditions, and therefore is poised to make significant contributions to the field of materials science as well as earth science. Brillouin scattering measurements will be attempted to temperatures of up to 2500 Kelvin, while the sample is simultaneously held at pressures of up to 50 GPa. Initial experiments will concentrate on careful characterization of the temperature/pressure environment (including accounting for thermal pressure), identifying sources of error in the method, and developing techniques for making the most accurate measurements possible. ***