Technique development of a MEMS-based heating stage for high-pressure transmission electron microscopy in the earth sciences

地球科学中高压透射电子显微镜用 MEMS 加热台的技术开发

• 批准号: 1148776
• 负责人: Peter Buseck
• 金额: $ 20.29万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-03-15 至 2015-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1148776&HistoricalAwards=false
• 关键词: Technique; development; MEMS; based; heating

Minerals at elevated pressure (P) and temperature (T) provide essential information about the interior of Earth and other planets. Knowledge of their properties and phase transitions under extreme conditions provides unique insights into seismic discontinuities, mantle plumes, mantle turnover, and other dynamic effects that occur inside planets. Transmission electron microscopes (TEMs) are the only instruments that provide the resolution needed to study high-P minerals at the atomic level. Controlled sample heating within a TEM is critical for the high-P measurements. However, it is highly challenging to obtain the required mechanical stability, minimal thermal drift, and rapid settle times, all within the small sample area of a TEM. Heating stages have recently been greatly superseded in thermal and mechanical stability, and thereby accuracy, by a totally new design for TEMs that is based on MEMS (micro-electro-mechanical systems) technology on tiny solid-state chips. This technology also permits analytical electron microscopy (AEM), including energy-dispersive X-ray spectroscopy (EDS), at elevated temperatures. Such analyses at high Ts were heretofore not possible in a TEM. MEMS heating systems have not yet been used in the earth sciences. The goal of this project is to develop this method of heating within a TEM and its utilization for studying minerals at mantle conditions. We anticipate that the results of these developments will provide a significant improvement and expansion of high-P measurements. It will be possible, for the first time, to observe the structure, behavior, and properties of earth materials at atomic resolution in situ at the PT conditions in Earth?s lower crust and mantle. The results will provide fundamental new knowledge about the nature of geologically and geophysically important minerals at extreme conditions.

高压 (P) 和温度 (T) 下的矿物提供了有关地球和其他行星内部的重要信息。了解它们在极端条件下的特性和相变，为了解地震不连续性、地幔柱、地幔翻转和行星内部发生的其他动态效应提供了独特的见解。透射电子显微镜 (TEM) 是唯一能够提供原子水平研究高磷矿物所需分辨率的仪器。 TEM 内受控的样品加热对于高 P 测量至关重要。然而，在 TEM 的小样品区域内获得所需的机械稳定性、最小的热漂移和快速的稳定时间非常具有挑战性。最近，基于微型固态芯片上 MEMS（微机电系统）技术的全新 TEM 设计，在热稳定性和机械稳定性方面以及准确性方面已大大取代了加热台。该技术还允许在高温下进行分析电子显微镜 (AEM)，包括能量色散 X 射线光谱 (EDS)。迄今为止，在 TEM 中不可能进行此类高 Ts 分析。 MEMS 加热系统尚未应用于地球科学。 该项目的目标是开发这种在 TEM 内加热的方法，并将其用于研究地幔条件下的矿物。我们预计这些发展的结果将显着改进和扩展高 P 测量。首次有可能在地球下地壳和地幔的 PT 条件下以原子分辨率原位观察地球材料的结构、行为和性质。研究结果将提供有关极端条件下地质和地球物理重要矿物性质的基本新知识。