Development of the Next Generation Megabar High-Pressure Cells: A COMPRES Grand Challenge

0135626 Hemley我们建议开发下一代静态超高压装置，该装置将允许在兆巴压力下将样品体积增加超过常规金刚石单元中目前可用的样品体积的100倍。这将使目前无法用于超高压研究的无数主流分析技术成为可能，包括成功利用即将上线的主要中子和同步辐射设施所需的技术。新型高压单元还将提高现有原位探针技术的测量精度，提供校准良好的静水压力和均匀的温度，允许通过激光加热实现更高和更均匀的温度，并提供稳健和用户友好的操作。需要这些能力来解决高压地球化学，地球物理学和行星科学中的许多当前问题;因此，预计拟议的进展将在这些领域中的每一个产生重大影响。新细胞的样品体积增加将是由于多种改进的组合，包括扩大的砧座、修改的底脚形状、设计的垫圈和增加的砧座结合支撑。在高压和高温下合成的单晶金刚石将通过单晶金刚石薄膜的同质外延化学气相沉积过度生长而扩大，以产生达到25克拉以上的砧。合成碳硅石（SiC）砧将用于测试，并在高达50 GPa的压力下增加100倍的体积。更大的样品室，反过来，将消除目前由微观体积施加的限制，并大大改善压力-温度条件和探测能力，在超高压。将建造新的印刷机，以提供更大容量所需的负载。该项目将与新成立的地球科学材料特性研究理事会协调进行，通过该理事会，将向高压地球科学界提供新的高压能力。

0135626HemleyWe propose to develop the next generation static ultrahigh-pressure apparatus that will allow an increase in sample volumes in excess of 100 times those currently available in conventional diamond cells at megabar pressures. This will enable myriad mainstream analytical techniques currently unavailable for ultrahigh-pressure research, including those required for the successful utilization of major neutron and synchrotron radiation facilities that are coming on line. The new class of high-pressure cells will also improve measurement accuracy for existing in situ probe techniques, provide well-calibrated hydrostatic pressures and uniform temperatures, allow higher and more uniform temperatures to be achieved with laser heating, and provide robust and user-friendly operation. These capabilities are required to address numerous current problems in high-pressure geochemistry, geophysics, and planetary science; as such, the proposed advances are expected to have major impact in each of these areas. The increases in sample volume for the new cells will result from a combination of improvements that include enlarged anvils, modified culet shapes, designed gaskets, and added binding support for the anvils. Single-crystal diamonds synthesized at high pressures and temperatures will be enlarged by homoepitaxial chemical vapor deposition overgrowth of single-crystal diamond films to create anvils reaching 25 carats and above. Synthetic moissanite (SiC) anvils will be used for testing and for 100-fold volume increases at pressures up to 50 GPa. The larger sample chamber, in turn, will remove restrictions currently imposed by microscopic volumes and greatly improve the pressure-temperature conditions and probing capabilities at ultrahigh pressures. New presses will be built to provide the loads necessary for the larger volumes. The project will be carried out in coordination with the newly formed COnsortium for Materials Properties Research in the Earth Sciences (COMPRES), through which the new high-pressure capabilities will be made available to the high-pressure geoscience community.***