200kV Transmission electron microscope

目前电子显微镜领域的发展越来越多地向三维描述超微结构特征的方向发展，这推动了电子层析成像的实现。电子断层扫描是海德堡大学电子显微镜核心设备(EMCF)提供的技术之一，该设备为大学所有成员提供透射和扫描电子显微镜的技术和科学支持。我们正在申请一台200千伏的透射式电子显微镜，它带有一个场发射枪，这是高质量电子断层扫描的标准，以及一个底部安装的CMOS4K相机和一个扫描透射式电子显微镜(STEM)探测器。我们计划将该显微镜用于对核心设备庞大用户群进行最先进的成像所必需的三个目的。首先，该显微镜将是3D电子显微镜的主要机器，即对树脂嵌入材料的部分进行高分辨率电子断层扫描，从而能够在设施的组合中维护和改进这项技术。其次，STEM探测器将使我们能够使用更新的STEM断层扫描技术，满足对生物样本的高分辨率、大体积成像的需求。茎断层扫描可以将截面厚度增加约三倍，并具有高空间分辨率，这是许多在细胞环境中研究结构的EMCF用户的需求。使用STEM时增加的截面厚度也是通过相关光学和电子显微镜瞄准特定结构时的优势，这是EMCF已经提供的一项技术，因为用户对瞄准稀有和小结构的需求越来越大。第三，更新仪器是必要的，因为校园里每个人都可以拿到的三台用于树脂包埋样品的EMCF透射电子显微镜要么出了故障，要么即将报废。为了防止向科学界提供的服务因显微镜故障而中断，我们需要确保该设施的透射电子显微镜及时实现现代化。由于现代显微镜的多功能性，允许在不同电压之间切换并调用保存的对准，因此该仪器不仅将取代现有的仪器，而且还将作为常规薄片2D EM的备用仪器。

Current developments in the field of electron microscopy increasingly move in the direction of describing ultrastructural features in 3D, which drives the implementation of electron tomography. Electron tomography is one of the techniques offered by the Electron Microscopy Core Facility (EMCF) at Heidelberg University, a facility which provides technical and scientific support for transmission and scanning electron microscopy to all members of the university. We are applying for a 200kV transmission electron microscope (TEM) with a field emission gun, which is standard for good quality electron tomography, and a bottom mounted CMOS 4K camera as well as a scanning transmission electron microscope (STEM) detector. We plan to use the microscope for three purposes essential for state-of-the-art imaging of the Core Facility’s large user base. Firstly, the microscope will be the primary machine for 3D electron microscopy, that is high resolution electron tomography of sections of resin embedded material, allowing to maintain and improve this technique in the portfolio of the facility. Secondly, the STEM detector will enable us to use the more recent STEM tomography technology, addressing the demand for high-resolution, large-volume imaging of biological specimens. STEM tomography allows to increase the section thickness about threefold with high spatial resolution and is demanded by many of the EMCF users who study structures in their cellular environment. The increased section thickness when using STEM is also an advantage when targeting specific structures by correlative light and electron microscopy, a technique already offered at the EMCF with increasing user demand for targeting rare and small structures. Thirdly, the renewal of instruments is necessary since the three EMCF transmission electron microscopes for resin embedded specimens, accessible by everyone on campus, are either out of order or are coming close to their end of life. To prevent an interruption in service to the scientific community due to malfunctioning microscopes we need to ensure a timely modernization of the TEM microscopes at the facility. Thanks to the versatility of modern microscopes, allowing switching between different voltages and recalling saved alignments, the instrument will therefore not only replace the existing instrument, but also act as a backup instrument for regular thin section 2D EM.