
NSF Org: |
EAR Division Of Earth Sciences |
Recipient: |
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Initial Amendment Date: | March 25, 2013 |
Latest Amendment Date: | March 25, 2013 |
Award Number: | 1128867 |
Award Instrument: | Standard Grant |
Program Manager: |
David Lambert
EAR Division Of Earth Sciences GEO Directorate for Geosciences |
Start Date: | April 1, 2013 |
End Date: | March 31, 2017 (Estimated) |
Total Intended Award Amount: | $145,340.00 |
Total Awarded Amount to Date: | $145,340.00 |
Funds Obligated to Date: |
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History of Investigator: |
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Recipient Sponsored Research Office: |
5241 BROAD BRANCH RD NW WASHINGTON DC US 20015-1305 (202)387-6400 |
Sponsor Congressional District: |
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Primary Place of Performance: |
5251 Broad Branch Road NW Washington DC US 20015-1305 |
Primary Place of
Performance Congressional District: |
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Unique Entity Identifier (UEI): |
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Parent UEI: |
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NSF Program(s): | Instrumentation & Facilities |
Primary Program Source: |
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Program Reference Code(s): | |
Program Element Code(s): |
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Award Agency Code: | 4900 |
Fund Agency Code: | 4900 |
Assistance Listing Number(s): | 47.050 |
ABSTRACT
Knowledge of elasticity of Earth and planetary materials is needed for interpretation of the seismic anomalies, evaluation of the Earth?s and other planets compositional and dynamical models, while their transport properties (thermal and electrical conductivity) are the key parameters controlling the thermal history of the core and mantle and their dynamics. These properties are related to the planetary accretion and differentiation, the time evolution of mantle and core temperatures, and the generation of the Earth?s magnetic field.
In spite of numerous recent technical developments, in situ measurements of the above listed materials properties under extreme conditions remain a challenging problem. This project will develop new, fast, fs laser-based instrumentation for in situ measurements of elasticity and transport properties (thermal and energy dependent optical conductivity) of materials subjected to extreme high pressure and temperature (P-T) in the diamond anvil cell (DAC). The project team will adapt the existing acoustic interferometry (AI) and time-domain thermoreflectance (TDTR) techniques for the pulsed laser heated DAC technology developed by this research group. They will design and build a broadband spectroscopy (BBOS) setup, which will allow in situ measurement of material optical properties at high P-T conditions from ultraviolet to mid infrared using an ultra-bright pulsed fs laser source.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The major goal of the project is to develop new fast laser-based instruments for in situ measurements transport properties (thermal and energy dependent optical conductivity) and elasticity of materials subjected to extreme high pressure and temperature (P-T).
We have developed three major laser optical systems that are designed to work with diamond anvil cells (DAC) generating simultaneous conditions of high pressure and high temperature (P-T):
(i) Transient heating (TH) system, which combines pulsed laser heating and time domain radiometric temperature measurements for measurements of lattice thermal conductivity [1].
(ii) Broad band optical spectroscopy (BBOS) system in visible and near infrared spectral ranges (IR) for determination of radiative thermal conductivity via the measurements of the optical properties of materials in situ at simultaneous conditions of high P-T in a laser heated diamond anvil cell (DAC). This system utilizes a very bright white light source of a supercontinuum laser and time-resolved spectroscopic measurements in visible and near infrared (IR) spectral ranges [2-6].
(iii) Time domain thermoreflectance (TDTR) for elasticity (acoustic interferometry, AI) and thermal conductivity measurements. This is an ultrafast pump-probe system which utilizes a 100’s femtosecond (fs) Titanium: Sapphire laser (oscillator) for measurements of the sound velocities in the time domain [7].
Our technical developments enable a number of studies on lattice and radiative conductivity of the Earth's mantle and core materials (mantle minerals, Fe alloys, and model compounds) which provide new insights into its composition and state, interior heat transport, and history of the thermal evolution. These results have implications for developments of models of heat transport in the Earth’s lower mantle and presence of dark-magmas at the Earth's core-mantle boundary.
Moreover, our technical developments empowered in situ optical experiments at extreme pressures and temperatures on a number of planetary materials with the implications for the structure and compositions of planetary interiors. Using our visible BBOS system, we have performed experiments on optical properties of Xe, Ar, Ne, He, H2, O2, N2, MgO, H2O, CH4 compressed in the DAC up to 150 GPa and pulsed laser heated up to 15,000 K. We find that unlike the previous anticipations N2, Ar, Ne, and H2 show semiconducting behavior at high temperatures. However, our preliminary measurements for H2, N2, and CH4 show a crossover to a metallic state.
The pulsed laser techniques developed in this project open principally new possibilities to study the Earth's material at high pressure and high temperatures: elasticity and transport properties will be measured directly at the relevant for the Earth’s interior pressure-temperature conditions. This new knowledge will help modelers and thus provide better understanding of the Earth’s and planetary dynamics and thermal history.
[1] Z. Konôpková, R.S. McWilliams, N. Gómez-Pérez, A.F. Goncharov, Direct measurement of thermal conductivity in solid iron at planetary core conditions, Nature, 534 (2016) 99-101.
[2] R.S. McWilliams, D.A. Dalton, Z. Konôpková, M.F. Mahmood, A.F. Goncharov, Opacity and conductivity measurements in noble gases at conditions of planetary and stellar interiors, PNAS, 112 (2015) 7925-7930
[3] R.S. McWilliams, D.A. Dalton, M.F. Mahmood, A.F. Goncharov, Optical Properties of Fluid Hydrogen at the Transition to a Conducting State, Phys. Rev. Lett., 116 (2016) 255501.
[4] S.S. Lobanov, N. Holtgrewe, J.F. Lin, A.F. Goncharov, Radiative conductivity and abundance of post-perovskite in the lowermost mantle, arXiv, DOI (2016) arXiv:1609.06996.
[5] S.S. Lobanov, N. Holtgrewe, A.F. Goncharov, Reduced radiative conductivity of low spin FeO6-octahedra in FeCO3 at high pressure and temperature, Earth Planet. Sci. Lett., 449 (2016) 20-25.
[6] S.S. Lobanov, A.F. Goncharov, K.D. Litasov, Optical properties of siderite (FeCO3) across the spin transition: Crossover to iron-rich carbonates in the lower mantle, Am. Mineral., 100 (2015) 1059-1064.
[7] A.F. Goncharov, F. Decremps, M. Gauthier, S. Ayrinhac, D. Antonangeli, Y.A. Freiman, A. Grechnev, S.M. Tretyak, Elasticity of Hydrogen at High Pressures, American Geophysical Union, Fall Meeting 2015, abstract #MR13C-2726; PRB submitted (2015).
Last Modified: 05/03/2017
Modified by: Alexander F Goncharov
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