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Measurement of thermal diffusivity at high pressures and temperatures using synchrotron radiography

Published online by Cambridge University Press:  05 July 2018

D. P. Dobson*
Affiliation:
Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK
S. A. Hunt
Affiliation:
Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK
L. Li
Affiliation:
Department of Geosciences, Mineral Physics Institute, State University of New York at Stony Brook, Stony Brook, NY, 11794-2100, USA
D. Weidner
Affiliation:
Department of Geosciences, Mineral Physics Institute, State University of New York at Stony Brook, Stony Brook, NY, 11794-2100, USA
*

Abstract

A new method to measure thermal diffusivity in samples at simultaneous high pressure and high temperature is presented. The sample is placed inside a cylindrical heater and subjected to a heater power that varies sinusoidally with time. The diffusion of the temperature variations into the sample is monitored using radiographic imaging of marker foils. This provides measurements of the phase lag and amplitude variation of the temperature cycle at a range of radii from the sample axis without the need for multiple thermocouples. The technique is tested using a NaCl sample at 4 GPa; the best-fit thermal diffusivity for NaCl at 4 GPa and 673 K is 2.4±0.5x10-6 m2/s.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2008

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