MRI: Acquisition of a Direct Detection Electron Camera for an Existing Scanning Transmission Electron Microscope for Low-Dose and Phase-Sensitive Imaging of Materials

非技术描述：这项主要研究仪器项目的目的是为俄勒冈大学的透射电子显微镜获得一个直接电子检测相机。俄勒冈州先进材料表征中心（CAMCOR）的共享电子显微镜设施为对分析各种天然和工程材料和设备的结构和性能感兴趣的研究人员提供了区域资源。电子显微镜是成像和测量材料的原子结构和组成的重要工具，但有些材料在电子束照射下会迅速损坏。此外，由于对比度低，许多结构和过程难以用传统相机成像。这款新相机的效率和速度更高，在图像细节和对比度方面有了很大的改进，能够对剂量敏感的样品进行成像，并提供纳米尺度下快速过程的视频，所有这些对表征先进材料都很重要。作为支持众多扩展和教育机会的现有基础设施的一部分，直接电子探测器也用于西北地区不同年龄、学科和学术阶段的用户的一系列课程和专业发展机会。本科生、研究生和博士后研究人员获得电子显微镜操作和分析以及大型图像数据集的生成、处理和处理方面的可转移技能的实践经验。这个探测器加强了现有的夏季研究课程，旨在吸引本科生参与纳米科学和物理研究。技术描述：直接电子探测器以快速记录高分辨率电子图像的固有能力被应用于低对比度动态过程的观察，例如透射电子显微镜的液体电池样品支架中的氧化催化，锂离子电池在充放电循环中不断变化的阴极材料结构，以及纳米尺度上材料的结晶动力学。新型探测器的高检测效率也被用于发展电子干涉测量技术。电子在相干叠加路径结合形成干涉图案，提供提高灵敏度的标本。该探测器能够在电子干涉仪的输出端记录单电子事件，从而实现量子启发的测量协议，如无相互作用测量和增强相位成像。通过这种方式，直接电子探测器为研究人员提供了更大的机会来研究和理解更广泛的材料系统和过程，以及进行量子力学实验。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-Technical Description:The purpose of this major research instrumentation project is to acquire a direct electron detection camera for a transmission electron microscope at the University of Oregon. The shared-use electron microscopy facility in the Center for Advanced Materials Characterization in Oregon (CAMCOR) serves as a regional resource for researchers interested in analyzing the structure and properties of a variety of natural and engineered materials and devices. Electron microscopy is an important tool for imaging and measuring the atomic structure and composition of materials, but some materials are quickly damaged by exposure to an electron beam. Furthermore, many structures and processes are difficult to image using conventional cameras because of low contrast. The higher efficiency and speed of this new camera delivers large improvements in image detail and contrast, enabling imaging of dose-sensitive samples and providing videos of fast processes at the nanometer scale, all of which are important to the characterization of advanced materials. As part of an existing infrastructure supporting numerous outreach and educational opportunities, the direct electron detector is also used for an array of curriculum and professional development opportunities for users across age, disciplines, and academic stages across the Northwest. Undergraduate, graduate, and postdoctoral researchers obtain hands-on experience learning transferrable skills in electron microscope operation and analysis, and in the generation, handling, and processing of large image datasets. This detector strengthens an existing summer research course designed to engage undergraduates in nanoscience and physics research.Technical Description:The native ability of the direct electron detector to record high-resolution electron images at rapid speeds is applied to observations of low-contrast dynamic processes, such as oxidation catalysis in a liquid cell sample holder for a transmission electron microscope, the evolving cathode material structure throughout charge/discharge cycles in lithium-ion batteries, and crystallization kinetics of materials at the nanoscale. The high detection efficiency of the new detector is also used to develop electron interferometry techniques. Electrons in a coherent superposition of paths combine to form an interference pattern, providing enhanced sensitivity to specimens. The detector's ability to record single-electron events at the output of an electron interferometer enables quantum-inspired measurement protocols such as interaction-free measurements and enhanced phase imaging. In this way, the direct electron detector provides researchers with a greater opportunity to study and understand a wider variety of material systems and processes as well as to perform quantum mechanical experiments.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.