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Prototype instrument development and improvement is an ongoing process with each achievement paving the way for new advances. In 2015, principal investigator Alex Goncharov started a new collaboration with scientists from the University of Pierre and Marie Curie in Paris, France, including Prof. F. Decremps, an expert in laser ultrasonics. The group has measured sound velocities of H2 and D2 up to 55 GPa in Paris. Next, with support from the Carnegie Institution of Washington, they will establish a laser ultrasonics system at the Geophysical Laboratory in Washington, DC. This additional capability will allow researchers to obtain revolutionary measurements, including the reaction mechanisms and kinetics of abiotic hydrocarbon generation, determination of sound velocities, and measurement of thermal conductivity of fluids under conditions of very high P (100 GPa) and T (4000°K). The science team is finalizing the proposed system’s design, but to continue advancing the instrument’s development and further leverage the DCO investment, Goncharov is submitting instrument proposals to multiple funding sources in the US and China.
A DCO Decadal Goal is to understand the physics and chemistry of carbon at the conditions of Earth’s deep interior. Such advances rely on developing comprehensive thermodynamic models of phase stability and physical properties of C-H-O fluid systems and their interactions with other deep phases—models that rely on as yet unknown thermodynamic properties of C-bearing materials. A prototype instrument being developed with DCO support aims to rapidly determine thermodynamic properties at submicron length scales to enable measurements in previously unattainable pressure-temperature regimes. This capability will allow researchers to obtain revolutionary measurements, including the reaction mechanisms and kinetics of abiotic hydrocarbon generation, determination of sound velocities, and measurement of thermal conductivity of fluids under conditions of very high P (100 GPa) and T (4000°K).
Setting up the new system required two major components: a dedicated fiber laser to heat the sample and a detector to measure temperature. Principal investigator Alex Goncharov purchased the detector and leveraged DOE EFree program funds to hire a postdoc who substantially improved the time-domain thermoreflectance (TDTR) component that previously had limited time resolution. The radiometry temperature measurements using the new detector were also set up and tested. The science team has also working to finalize the proposed system’s design.
- A flash heating method for measuring thermal conductivity at high pressure and temperature: Application to Pt
- Direct measurement of thermal conductivity in solid iron at planetary core conditions
- Experimental study of thermal conductivity at high pressures: Implications for the deep Earth’s interior
- Metallization and molecular dissociation of dense fluid nitrogen
- Opacity and conductivity measurements in noble gases at conditions of planetary and stellar interiors
- Optical Properties of Fluid Hydrogen at the Transition to a Conducting State
- Radiative conductivity and abundance of post-perovskite in the lowermost mantle
- Raman spectroscopy and x-ray diffraction of sp3 CaCO3 at lower mantle pressures
- Reduced radiative conductivity of low spin FeO6-octahedra in FeCO3 at high pressure and temperature