MR025-06
High-temperature, high-pressure behavior of lithium fluoride

Wednesday, 16 December 2020: 08:50
Virtual
Kanani K M Lee1, Sarah M Arveson2, Yue Meng3, Markus Daene1, Eric C. Dutra4, Sebastien Hamel5 and Minta C Akin5, (1)Lawrence Livermore National Laboratory, Physics, Livermore, CA, United States, (2)University of California Berkeley, Earth and Planetary Science, Berkeley, CA, United States, (3)HPCAT, X-Ray Science Division, Argonne National Laboratory, Argonne, United States, (4)Nevada National Security Site, Livermore, United States, (5)Lawrence Livermore National Laboratory, Livermore, CA, United States
Recorded Presentation
Abstract:
Lithium fluoride (LiF) is used extensively as a pressure medium and as thermal insulation in diamond-anvil cell (DAC) experiments; and is also used as optical windows in dynamic compression experiments. In order to better understand this important high-pressure standard and ubiquitous window material, we present high-temperature isothermal equations of state of LiF below its melting curve as measured in a laser-heated DAC. In order to avoid the rapid changes in optical absorption exhibited by LiF and other alkali halides when heated at high temperatures (e.g., [Arveson et al., PRB, 2018; Boehler et al., PRL, 1997]), we sputter coat LiF foils with Mo to protect LiF from defect formation due to laser irradiation. This change in sample preparation allows, for the first time, LiF volumes to be measured above the melt line. Additionally, we explore further changes in optical properties due to defect formation due to x-ray irradiation and the significant consequences this has for temperature measurements measured spectroscopically.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-795563.

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