MRI: Acquisition of a High Resolution Low Voltage Electron Microscope for Multidisciplinary Needs at The University of Georgia

这一重大研究仪器(MRI)奖支持佐治亚大学(UGA)购买一台高分辨率低电压电子显微镜，使研究人员能够在物理科学、地质和环境科学、生物科学、工程学科和相关领域进行研究、培训、教学和推广工作。该显微镜具有独特的技术能力，可以在减轻电子束损伤的条件下对样品进行成像和化学分析。这些能力导致了对包括纳米结构、聚合物、纤维和生物标本在内的各种材料的研究，这包括由29个主要用户在UGA的许多学院、中心、系和实验室进行的研究。该仪器集成在佐治亚大学的佐治亚电子显微镜(GEM)核心设施中，以实现跨学科和跨学科的使用和合作。除了研究应用和对学生用户的相关培训外，新显微镜还能够在课程设置和推广工作中包含最先进的电子显微镜内容。这些活动部分是利用GEM的电子剧场完成的，重点是环境中的纳米科学。此外，该仪器还用于获取适合整合到K-12 STEM课程计划中的数据集。该MRI奖支持购买能够低电压操作(定义为小于或等于30千伏)的电子显微镜。该仪器的技术亮点包括低压超高分辨率扫描电子显微镜(UHR-SEM)成像；高分辨率扫描电子显微镜(STEM)模式，包括高角度环形暗场(HAADF)成像和其他探测器，均在低束电压下工作；以及分析工具，提供定量成分和结构数据，包括电子衍射、通过能量色散X射线光谱仪(EDS)进行的元素图谱和电子能量损失谱(EELS)，所有这些都在低压下进行。该仪器支持的研究项目跨越四个主题领域：(1)无机纳米材料，特别是用于储能、电子应用、生物医学成像和药物输送的功能材料，(2)纳米地球科学和环境土壤科学，(3)开发高分辨率低电压方法成像生物样品的新前沿，以及(4)纳米结构混合系统和软材料的高分辨率低电压成像，包括聚合物和纤维等对光束敏感的样品。特别是，将电子显微镜应用于束敏感材料将在纳米尺度上提供关于样品组成、异质性、结构、相纯度和性质的新的详细信息。此外，与透射电子显微镜成像相比，STEM Brightfield和HAADF成像模式的卓越对比度将使研究人员能够解析详细的有机成分，如无机纳米结构的配位体日冕和生物结构之间的界面。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This Major Research Instrumentation (MRI) award supports the acquisition of a high-resolution low-voltage electron microscope at the University of Georgia (UGA) that enables the research, training, teaching, and outreach efforts of investigators across the physical sciences, geological and environmental sciences, biological sciences, engineering disciplines, and allied fields. The unique technical capabilities of this microscope allow the imaging and chemical analysis of samples under conditions that mitigate electron beam damage. These capabilities lead to the study of diverse materials including nanostructures, polymers, fibers, and biological specimens, which encompass research being done by 29 major users across numerous colleges, centers, departments, and laboratories at UGA. This instrument is integrated within the Georgia Electron Microscopy (GEM) core facility at UGA to permit inter- and transdisciplinary usage and collaboration. Beyond research applications and the associated training of student users, the new microscope enables the inclusion of state-of-the-art electron microscopy content in course offerings and outreach efforts. These activities are accomplished in part using GEM's Electron Theater, with an emphasis on nanoscience in the environment. In addition, the instrument is used to acquire data sets suitable for integration into K-12 STEM lesson plans.This MRI award supports the acquisition of an electron microscope capable of low-voltage operation (defined as less than or equal to 30 kV). The technical highlights of this instrument include ultra high-resolution scanning electron microscopy (UHR-SEM) imaging at low voltages; high resolution scanning transmission electron microscopy (STEM) mode, including high-angle annular dark field (HAADF) imaging and additional detectors, all operating at a low beam voltage; and analytical tools that provide quantitative composition and structure data, including electron diffraction, elemental mapping by energy dispersive X-ray spectroscopy (EDS), and electron energy-loss spectroscopy (EELS), all at low voltages. Research projects enabled by this instrument span four thematic areas: (1) inorganic nanomaterials, especially 2D nanosheets and functional materials for energy storage, electronics applications, biomedical imaging, and drug delivery applications, (2) nanogeoscience and environmental soil science, (3) new frontiers in developing high-resolution low-voltage methods for imaging biological specimens, and (4) high-resolution low-voltage imaging of nanostructured hybrid systems and soft materials, including beam-sensitive samples like polymers and fibers. In particular, the application of electron microscopy to beam-sensitive materials will provide new detailed information about sample composition, heterogeneity, structure, phase purity, and properties at the nanoscale. Additionally, the superior contrast in STEM brightfield and HAADF imaging modes, compared with TEM imaging, will allow investigators to resolve detailed organic components, such as the ligand coronas of inorganic nanostructures and interfaces between biological structures.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.