MRI: Development of an ultrafast, ultrasensitive, and high resolution direct electron detector for next-generation electron back-scattered diffraction of metallic and beam-sensitiv

电子背散射衍射(EBSD)已经发展成为一种广泛而强大的表征技术，用于绘制和分析材料中的相，提供关于晶体取向、形貌、晶格应变、拓扑和晶体织构的关键信息。由于用于低剂量成像的单电子灵敏度和用于时间分辨研究的超快探测，避免了电子和光子之间的低效转换的直接电子探测的出现彻底改变了透射电子显微镜领域，但它在扫描电子显微镜(SEM)中的应用还处于起步阶段。加州大学圣巴巴拉分校被授予为广泛使用的扫描电子显微镜平台开发超快和超灵敏的直接电子EBSD仪器，为因电子束损伤和探测器的时间限制而受阻的材料研究提供了丰富的机会。该开发项目改进了最先进的EBSD采集速度，并通过新的传感器设计提高了灵敏度，解决了添加制造材料和受束流损坏困扰的新兴剂量敏感型能量存储和转换材料的快速3D表征方面最棘手的挑战。该奖项将确保通过由共享用户设施主办的年度开放参观活动与社区和职业早期研究人员接触，以及通过与加州大学圣巴巴拉分校材料研究实验室和量子铸造公司的伙伴关系参与REU和RET项目。开发的仪器和模拟工具还将与科学计算中心集成，该中心将促进高性能计算在研究和教学环境中的有效使用。下一代直接检测EBSD仪器将优化为具有单电子灵敏度的3KV至30KV电子束能量，以及允许在显微镜腔内灵活放置的小传感器形状因数。对于易受损伤的材料，如有机晶体材料，限制电子剂量是至关重要的，探测效率变得至关重要，特别是在低能时。开发的仪器将能够检测到电子衍射中编码的丰富材料信息，绕过了长期存在的低损伤阈值和弱散射信号的问题。金属合金和电池材料也受益于高检测灵敏度和低千伏操作，揭示了额外制造的材料中的位错细胞等结构特征，并使微观结构的演变速度能够跟上操作设备观察的速度。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。

Electron back-scattered diffraction (EBSD) has evolved into a widespread and powerful characterization technique for the mapping and analysis of phases in materials, providing key information about crystal orientation, morphologies, lattice strain, topology, and crystallographic texture. The advent of direct electron detection that circumvents inefficient conversion between electrons and photons has revolutionized the field of transmission electron microscopy owing to single-electron sensitivity for low-dose imaging and ultrafast detection for time-resolved studies, but its use in scanning electron microscopes (SEMs) is in its infancy. An award is made to the University of California Santa Barbara to develop an ultrafast and ultrasensitive direct electron EBSD instrument for the widely accessible SEM platform, providing a rich opportunity for materials research that are hindered by electron beam damage and temporal limitations of detectors. The development project improves on the state-of-the-art EBSD acquisition speed and enhances the sensitivity through a new sensor design, unlocking the most vexing challenges in the rapid 3D characterization of additively manufactured materials and emerging dose-sensitive energy storage and conversion materials plagued by beam damage. The award will ensure engagement with the community and early-career researchers via a yearly open house hosted by the shared user facility, as well as with REU and RET projects through partnerships with the Materials Research Laboratory and the Quantum Foundry at UC Santa Barbara. The developed instrumentation and simulation tools will also be integrated with the Center for Scientific Computing, which promotes the effective use of High Performance Computing in the research and teaching environment.The next-generation direct-detection EBSD instrument will be optimized for electron beam energies of 3kV to 30kV with single-electron sensitivity, and a small sensor form factor permitting flexible location within the microscope chamber. For materials that are damage-prone, such as organic crystalline materials, limiting the electron dose is critical and detection yield becomes paramount, especially at low energies. The developed instrument will enable the detection of rich material information encoded in electron diffraction, circumventing longstanding issues of low-damage threshold and weak scattering signals. Metallic alloys and battery materials also benefit from high detection sensitivity and low-kV operation, revealing structural features such as dislocation cells in additively manufactured materials and enabling the evolution of microstructure at rates that can keep up with in operando device observations.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.