MRI: Development of a high energy-loss electron spectrometry system with improved detection sensitivity for an advanced electron microscope

电子能量损失光谱（EELS）在（扫描）透射电子显微镜中已成为表征材料的重要工具。EELS可以提供有关化学成分和键合的信息，这与几个大型设施中可用的同步加速器x射线方法产生的信息相似。在这个研究项目中，将开发一种新型的EELS系统，它比现有系统更通用，可以检测到更多的元素。它的优势还在于大大提高了纳米尺度的空间分辨率，这比同步加速器源所能达到的要好得多。新的EELS系统有效地将（扫描）透射电子显微镜转换为相当于同步加速器的设备，但提高了空间分辨率。该仪器的开发将影响从半导体到先进合金等材料科学广泛领域的广泛研究活动。它不仅将支持里海大学内部的项目，还将支持其他大学、政府实验室和行业的项目。所开发的知识将通过PI/co-PI教授的课程呈现给许多理哈伊学生，也将呈现给理哈伊显微镜学校的众多行业/政府参与者。同步加速器和电子显微镜学界将组织一次联合研讨会，就这一丰富的重叠研究领域交流知识。新的EELS系统有四个主要组成部分：(1)改进光学设计的EELS光谱仪，用于检测高能量损耗电子；(2)超高灵敏度电子探测器，用于检测高能量损耗范围内的低信号；(3)多功能扫描发生器，用于柔性电子探针控制；(4)集成软件平台，用于高效控制光谱仪和探测器；同时，显微镜也可以记录高能量损失信号，同时保持高空间分辨率，并允许能量过滤成像。新的高能量损耗EELS系统将能够检测高达~13,000eV的能量损耗信号。这意味着新的EELS系统可以记录到Se （Z = 34，包括所有3d过渡金属），l -边到Tl （Z = 82，包括所有镧系）和m -边到U （Z = 92）。可用于EELS分析的材料系统将扩大，包括用于各种催化应用的金纳米颗粒、重元素高熵合金和基于稀土的发光二极管。通过这个开发项目创建的软件包将免费提供给未来的用户。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。

Electron energy loss spectrometry (EELS) in the (scanning) transmission electron microscope has become an essential tool for materials characterization. EELS can provide insight on chemical composition and bonding, which is similar information to that generated by synchrotron X-ray methods available at several large facilities. In this research project, a new type of EELS system will be developed, which is more versatile and can detect more elements than currently achievable in existing systems. It will also have the advantage of greatly improved spatial resolution down to the nanoscale, which is considerably better than can be achieved at synchrotron sources. The new EELS system effectively transforms the (scanning) transmission electron microscope into the equivalent of a synchrotron facility but with improved spatial resolution. This instrumentation developed will impact a wide range of research activities across broad sectors of materials science ranging from semiconductors to advanced alloys. It will support projects not only internal to Lehigh, but also from other universities, government labs and industry. The knowledge developed will be presented to many Lehigh students via classes taught by the PI/co-PIs and also to numerous industry/government attendees of the Lehigh Microscopy Schools. A joint symposium will be organized between the synchrotron and electron microscopy communities to exchange knowledge on this fertile overlapping research area.The new EELS system has four major components: (1) an EELS spectrometer with improved optics design for the detection of higher energy-loss electrons, (2) an ultra-high sensitivity electron detector for lower signal detection in the high-energy-loss range, (3) a multi-functionality scan generator for flexible electron probe control and (4) an integrated software platform to efficiently control not only the spectrometer and detector, but also the microscope to record high-energy-loss signals while maintaining high spatial resolution and allowing energy-filtered imaging. The new high-energy-loss EELS system will be able to detect energy-loss signals up to ~13,000eV. This means that K ionization edges up to Se (Z = 34, including all 3d transition metals), L-edges up to Tl (Z = 82, including all the lanthanoid series) and M-edges up to U (Z = 92) can be recorded by the new EELS system. The palette of materials systems that become accessible for EELS analysis will be broadened to include for example, gold nanoparticles for various catalytic applications, high entropy alloys with heavy elements and rare-earth based light-emitted diodes. The software packages created through this development project will be made freely available for future users.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.