Collaborative Research: High Pressure Calibration at High Temperatures

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。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细胞（DAC）研究的高压、高温校准秤。现有的压力刻度存在问题，特别是在高温下。通过x射线衍射密度测量和立方氮化硼（cBN）布里渊散射同步声速测量，提出了建立压力标度的方法。此外，还将进行拉曼P和T的测量。pi建议通过耦合方法将其他材料在不同温度和压力下的状态方程引用到cBN中。由于材料的性质在高压和高温下会发生变化，因此在DAC研究中很难将压力归因于材料。压力和温度效应已被注意到许多材料和测量技术（x射线，光学，荧光等）。cBN被认为是一种潜在的压力刻度校准剂，因为在DAC研究范围内，cBN的晶体结构在至少1000 GPa的相变下理论上是稳定的。DAC研究以及校准的压力标度将允许研究地球内部的物质相变，地球材料热特性研究和状态方程确定，以及材料相稳定性和化学。这项研究将产生一个初级压力刻度-在惰性材料上校准，适用于高T&amp；P工作。结果将允许在高T&amp；P下进行精确的x射线衍射、x射线光谱学和x射线散射测量。反过来，这将使深层地球物质的理论状态方程计算成为可能。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（每年夏天2-3名）。研究生和博士后也被推荐培养。

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.