Energy-Loss Spectroscopy in a Scanning Electron Microscope

这项提案要求为安装在SuperSTEM4上的新型电子能量损失光谱仪(EELS)提供资金，SuperSTEM4是日立SU9000高分辨率扫描电子显微镜，是EPSRC国家研究设施(NRF)高级电子显微镜(EM)仪器套件的一部分。SuperSTEM通过对其用户群提供的能力和服务进行持续和持续的审查来确定需求，为此，SuperSTEM最近在样品制备和上游样品表征的支撑设备上进行了大量投资。这项投资旨在确保该设施的主要高分辨率仪器上分配的波束时间最大化。这包括提供NRF的最新仪器SuperSTEM4，这是一种新型的低压(传输)扫描电子显微镜或(T)扫描电子显微镜，将0.2 nm以下的高空间分辨率(在30KV加速电压下)与扫描电子显微镜的灵活性和高通量能力相结合。这项EPSRC核心设备资本奖将使SuperSTEM4升级为具有传输几何结构的电子能量损失光谱仪，这是扫描电子显微镜中的一项独特功能。这将使该设施的用户在一次光束加速电压低于该设施的主要仪器(0.5-30千伏)的情况下，在高通量但高分辨率的显微镜内访问关于其样品的光谱信息。SuperSTEM4的STEM-in-a-SEM特性为人造样品的初步化学成像开辟了更大的长度范围，为设施主要仪器的后续调查提供了来自更广泛样品领域的更具代表性的信息。此外，由于仪器上安装了许多特定于扫描电子显微镜的探测器(如背向散射和二次电子探测器)，表面和地形信息将与EELS提供的化学信息同时获得，从而实现材料的多维表征(多信号支持基于数据融合的分析，并通过摄影测量汇编2D和3D信息)。由于其冷场发射电子源，SuperSTEM4固有的高分辨率(&lt；0.4 eV)还将确保获得可与更高千伏的SuperSTEM2相媲美的EELS中的化学和成键信息，也直接支持用户用于高端EELS应用，例如在等离子体或电子结构确定领域。该设备将帮助支持超过120名活跃用户的整个设施用户群，包括许多在该设施进行项目的早期职业研究人员和博士生，它还将吸引更广泛的研究基础的兴趣，这些研究基础能够利用易用性和相对更容易满足对样品质量的需求。

This proposal requests funding for a novel electron energy loss spectrometer (EELS) to be installed on SuperSTEM4, a Hitachi SU9000 high-resolution scanning electron microscope that is part of the instrumentation suite at SuperSTEM, the EPSRC National Research Facility (NRF) for Advanced Electron Microscopy (EM). In response to needs identified through a continuous and on-going review of capabilities and services offered to its user community, SuperSTEM recently made substantial investments in underpinning equipment for specimen preparation and upstream sample characterisation. This investment was directed at capabilities to ensure allocated beamtime on the Facility's main high-resolution instruments is maximised. This includes the provision of the NRF's newest instrument, SuperSTEM4, which is a novel type of low-voltage (transmission) scanning electron microscope, or (T)SEM, combining a high spatial resolution of below 0.2nm (at 30kV acceleration voltage) with the flexibility and high-throughput capabilities of an SEM. This EPSRC Capital Award for Core Equipment will enable the upgrade of SuperSTEM4 with an electron energy loss spectrometer in transmission geometry, a unique capability in an SEM. This will offer the Facility's users access to spectroscopic information on their samples at primary beam acceleration voltage lower than the Facility's main instrumentation (0.5-30kV), within a high-throughput yet high-resolution microscope. The STEM-in-a-SEM nature of SuperSTEM4 opens up larger length-scales for preliminary chemical imaging of fabricated samples, providing providing more representative information from wider areas of samples for subsequent investigation on the Facility's primary instruments. Furthermore, thanks to the numerous SEM-specific detectors installed on the instrument (e.g. backscattered and secondary electron detectors), surface and topographical information will be available simultaneously with chemical information from EELS, allowing for a multidimensional characterisation of materials (multiple signals enabling data-fusion-based analyses, with 2D and 3D information compiled through photogrammetry). Thanks to its cold-field-emission electron source, the native high resolution of SuperSTEM4 (<0.4eV) will also ensure chemical and bonding information in EELS comparable to the higher-kV SuperSTEM2 is obtained, also directly supporting users for high-end EELS applications, e.g. in the field of plasmonics or electronic structure determination. The equipment will help support the entire facility user base of over 120 active users, including numerous early career researchers and doctoral students with on-going projects at the facility, and it will also attract interest from a broadened research base able to take advantage of ease-of-use and relatively easier-to-meet demands regarding sample quality.