Collaborative Research: High Pressure Calibration at High Temperatures

0842057 /0842345贡恰罗夫/巴斯该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助。该提案寻求约47.8万美元的资金，以支持开发用于金刚石砧座（DAC）研究的高压，高温校准标度。现有的压力秤受到问题的困扰，特别是在高温下。提出了一种压力标度，通过X射线衍射进行密度测量，并同时使用立方氮化硼（cBN）上的布里渊散射声速测量。此外，将进行拉曼P和T测量。PI建议通过将方法耦合到单个压力标度中，在不同的温度和压力下通过cBN的状态方程参考其他材料。由于材料的性质在高温高压下会发生变化，因此在DAC研究中很难确定施加在材料上的压力。压力和温度的影响已经注意到许多材料和测量技术（X射线，光学，荧光等）。cBN被建议作为潜在的压力标度校准物，因为它的晶体结构在DAC研究范围内理论上对高达至少1000 GPa的相变是稳定的。DAC研究沿着校准的压力刻度将允许研究地球内部的物质相变、地球物质热性质研究和状态方程确定以及物质相稳定性和化学性质。这项研究将导致一个主要的压力规模-校准的惰性材料和适用于高T P工作。结果将允许精确的X射线衍射，X射线光谱学和X射线散射测量下的高T P，这反过来，将允许理论状态方程计算深地球材料。研究结果将广泛影响地球物理学、矿物物理学、地球化学和地球动力学。研究将涉及REU学生（每年夏季2-3）。研究生是博士后也建议进行培训。

0842057 / 0842345Goncharov / BassThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). This proposal seeks ~$478K in funding to support developing a high pressure, high temperature calibration scale for diamond anvil cell (DAC) studies. Existing pressure scales are plagued with issues particularly at high temperatures. Developing a pressure scale is proposed by performing density measurements by x-ray diffraction and concurrent sound velocity measurements using Brillouin scattering on cubic boron nitride (cBN). In addition, Raman P and T measurements will be made. The PIs propose to reference other materials though their equation of state to cBN at varying temperatures and pressures by coupling methodologies into a single pressure scale. Because material properties change under high pressure and temperature, it has been difficult to ascribe pressure exerted on materials in DAC studies. Pressure and temperature effects have been noted for numerous materials and measurement techniques (X-ray, optical, fluorescent, etc). cBN is suggested as a potential pressure scale calibrant as it's crystal structure is theoretically stable to phase transformation up to at least 1000 GPa within the range of DAC studies. DAC studies along with the calibrated pressure scale will allow studies into material phase transitions in the Earth's interior, Earth material thermal property studies and equation of state determinations, and material phase stability and chemistry. This study will result in a primary pressure scale - calibrated on an inert material and suitable for high T&P work. The outcome will allow accurate X-ray diffraction, X-ray spectroscopy, and X-ray scattering measurements under high T&P. This, in turn, will allow theoretical equation of state calculations for deep Earth materials. Results will broadly impact geophysics, mineral physics, geochemistry and geodynamics. Studies will involve REU students (2-3 per summer). Graduate students are post-docs are also proposed for training.