MRI: Development of a Direct Detection Energy Loss Spectroscopy System

MRI：直接检测能量损失光谱系统的开发

• 批准号: 1429661
• 负责人: Mitra Taheri
• 金额: $ 87.07万
• 依托单位: Drexel University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-15 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1429661&HistoricalAwards=false
• 关键词: MRI; Development; Direct; Detection; Energy

MRI: Development of a Direct Detection Energy Loss Spectroscopy SystemNontechnical: Characterizing dynamic processes and reactions---how atoms move--is necessary to tackle key scientific issues in energy, medicine, and nanotechnology. To address this need, a multidisciplinary team of researchers are developing a new ultrafast spectroscopy system based on direct-detection technology. This state-of-the-art system enables dynamic studies of electronic and structural behavior in a wide range of materials and represents the first time in situ electron energy loss spectroscopy is being introduced to the electron microscopy marketplace, thus creating far-reaching and interdisciplinary impacts in the field of electron microscopy. Drexel's central location among many of the nation's top institutions ensures exposure to myriad universities, laboratories, and users. The development team boasts various collaborations (both in the US and internationally), which gives the new system automatic visibility. Opportunities for education and outreach include leveraging the NSF-funded Louis Stokes Alliance for Minority Participation (LSAMP) program to recruit minority students to train and be educated within the context of electron microscopy and to take advantage of Drexel's renowned co-operative engineering education program. Technical: Energy loss spectroscopy is particularly useful to probe electronic states, band structure, and chemistry, and to improve contrast in materials. While significant advancements in electron optics have permitted fine probe analysis of structure and chemical bonding at the atomic level, the next frontier in transmission electron microscopy (TEM) relies on imaging dynamic processes and reactions beyond standard video frame rates. Key developments in post column energy filters and direct detection cameras have enabled experiments at fine temporal and spatial scales; while these developments have advanced research individually, it is clear that the combination of direct detection technology with energy filtered imaging and spectroscopy would have substantial benefits. To date, these techniques have not been combined due to the inherent mismatch between the low-dose requirements of the direct detection applications and the very high dynamic range of electron energy loss spectroscopy (EELS). This instrument development activity integrates a direct detection camera system and a high resolution spectrometer to allow for in situ EELS to be performed at low electron doses and high speeds. This unprecedented combination boosts the analytical sensitivity of inelastic scattering techniques and yields compositional and electronic structure mapping at sub-nanometer to atomic spatial scales, and high-speed (4000 frames per second) detection at low energies, permitting quantitative time-resolved data acquisition for rapid processes. The combination of expertise of energy filtering systems and energy loss spectroscopy with expertise in in situ and ultrafast TEM provides insight into key processes and bridges gaps in the understanding of mechanisms in various disciplines, with direct and specific impacts on (1) charge mediated properties in oxide and semiconductor heterostructures (2) ion transfer in energy storage materials, and (3) assembly mechanisms in biomedical and soft materials.

MRI：开发直接检测能量损耗光谱系统的系统非技术：表征动态过程和反应 - 原子如何移动 - 需要解决能源，医学和纳米技术方面的关键科学问题。为了满足这一需求，一个多学科的研究人员团队正在基于直接检测技术开发新的超快光谱系统。这种最先进的系统能够在各种材料中对电子和结构行为进行动态研究，并代表第一次原位电子能量损失光谱范围引入了电子显微镜市场，从而在电子显微镜领域产生了深远的角度和跨学科的影响。德雷克塞尔（Drexel）在美国许多顶级机构中的中心位置可确保接触无数的大学，实验室和用户。开发团队拥有各种合作（无论是在美国还是在国际上），这使新系统自动可见性。教育和推广的机会包括利用NSF资助的路易斯·斯托克斯联盟（Louis Stokes Alliance）进行少数群体参与计划（LSAMP）计划，以招募少数民族学生在电子显微镜检查的背景下进行培训和接受教育，并利用Drexel著名的合作工程教育计划。技术：能量损失光谱对于探测电子状态，带状结构和化学的特征特别有用，并改善了材料的对比度。尽管电子光学的显着进步允许对原子水平的结构和化学键进行精细的探针分析，但传输电子显微镜（TEM）的下一个前沿依赖于成像动态过程和超出标准视频框架速率的反应。后柱能量过滤器和直接检测摄像机的关键发展已在精细的时间和空间尺度上实现实验。尽管这些发展对单独进行了进行研究，但很明显，直接检测技术与能量过滤成像和光谱法的组合将具有可观的好处。 迄今为止，由于直接检测应用的低剂量要求与电子能量损耗光谱（EELS）的非常高动态范围之间的固有不匹配，这些技术尚未合并。该仪器开发活动集成了直接检测摄像头系统和高分辨率光谱仪，以便以低电子剂量和高速进行原位鳗鱼。这种前所未有的组合增强了非弹性散射技术的分析灵敏度，并产生在亚纳米处的组成和电子结构映射到原子空间尺度，以及在低能的高速检测（每秒4000帧），从而允许定量时间分解数据习惯快速处理。能源过滤系统和能量损失光谱的专业知识与原位和超快TEM方面的专业知识的结合提供了对关键过程和桥梁间隙的见解，并在对各个学科的机制的理解中，对（1）对（1）电荷介导的介导的介导的介导的特性在氧化物和半导体构造中的直接和特定影响（2）离子材料（2）离子材料（2）ION材料（2）ION材料（3）构图和（3）。