Combination of pulsed light heating thermoreflectance and laser-heated diamond anvil cell for in-situ high pressure-temperature thermal diffusivity measurements
Combination of pulsed light heating thermoreflectance and laser-heated diamond anvil cell for in-situ high pressure-temperature thermal diffusivity measurements
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DOI：
10.1063/1.5093343
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发表时间：
2019-07-01
影响因子：
1.6
通讯作者：
Ohta, Kenji
中科院分区：
文献类型：
--
作者：
Hasegawa, Akira;Yagi, Takashi;Ohta, Kenji
将热反射测量与激光加热金刚石压砧（LHDAC）技术相结合，研制了一种原位测量材料高温高压热扩散率的仪器。在LHDAC系统中，高功率连续波激光束照射装载到金刚石砧座（DAC）中的盘状金属样品的两面，以保持稳定的高温条件。在LHDAC系统的操作期间，根据640和740 nm之间的热辐射光谱来确定样品的温度，以符合普朗克定律。随后，脉冲激光束照射金属盘，以诱导样品内部的温度梯度，和瞬态温度，由热扩散引起的，由连续波探针激光器测量的热反射现象的基础上。我们确定的Pt和Fe的热导率高达约60 GPa和2000 K使用测得的热扩散率，并获得与以前的作品一致的值。压力和温度的不确定度估计约为10%，导热系数的不确定度估计约为15%。在这项研究中开发的系统，使我们能够确定在压力-温度条件下的地球深部的材料的热输运特性。
By combining thermoreflectance measurements and laser heated diamond anvil cell (LHDAC) techniques, an instrument for the measurement of in situ high pressure-temperature thermal diffusivity of materials was developed. In an LHDAC system, high-power continuous-wave laser beams irradiate both faces of a disk-shaped metal sample loaded into diamond anvil cells (DACs), to maintain a stable high-temperature condition. During the operation of the LHDAC system, temperature of the sample is determined from the thermal radiation spectrum between 640 and 740 nm to fit Planck's law. Subsequently, a pulsed laser beam irradiates the metal disk to induce a temperature gradient inside the sample, and the transient temperature, caused by heat diffusion, is measured by a continuous wave probe laser based on the thermoreflectance phenomenon. We determined the thermal conductivities of Pt and Fe up to approximately 60 GPa and 2000 K using the measured thermal diffusivities and obtained values consistent with previous works. The uncertainties in the pressure and the temperature are estimated to be approximately 10%, and that in the thermal conductivity is estimated to approximately 15%. The system developed in this study enables us to determine thermal transport properties of materials under pressure-temperature conditions of the deep Earth.