Cryo scanning electron microscope

该提案的主题是带有热发射器的低温扫描电子显微镜（cryo SEM），该显微镜特别满足检查导电性差的塑料基和生物样品的要求。除了在低加速电压下的高成像性能外，这还需要在低真空下工作模式和高灵敏度的能量色散x射线光谱（EDX）系统。对于敏感材料的样品制备，使用低温氩离子抛光有望制造高质量的截面，通过这种方法，在许多样品中获得了显著增加的SEM图像的信息价值，或者根本可以进行评估。使用低温处理装置，可以通过在制备和检查过程中用液氮冷却来检查在室温下不稳定的样品。同时，冷冻和解冻过程可以模拟，检查和监测使用扫描电镜成像。所要求的系统是对汉诺威莱布尼茨大学现有设备的补充。特别是，低温扫描电镜检查和样品制备使用氩离子抛光首次成为可能。使用该系统处理的重复研究任务包括纤维表面、非织造布、界面质量和纤维增强塑料开发中的失效机制的评估。对于纤维-基体附着力的评价，除断口分析外，还将采用氩离子抛光的截面分析。在开发新的塑料回收方法时，扫描电镜研究有助于分析复杂材料（包括多层复合材料）的结构，以便在此基础上制定合适的处理策略。对中间产品和最终产品的扫描电镜分析提供了加工步骤对材料特性影响的信息。在塑料的海洋可降解性项目中，将对实地试验的试验样品进行检查，这些样品往往显示出很大的生物覆盖率。通过氩离子抛光，可以在这里产生不破坏生物膜的横截面。这使得评估试件内部的降解机制成为可能。在冷冻技术的研究领域，研究了生物样品（悬浮细胞、组织）以及组合产品（来自组织工程和再生医学的细胞/组织的聚合物载体结构）的冷冻和解冻过程的工艺参数的影响。低温处理单元可以模拟典型的工艺步骤。同时，结构的影响可以量化的分辨率优于在IMP可用的冷冻显微镜。

The subject of the proposal is a cryo scanning electron microscope (cryo SEM) with a thermal emitter, which specifically meets the requirements for the examination of poorly conductive plastic-based and biological samples. In addition to a high imaging performance at low acceleration voltages, this requires an operating mode in low vacuum and a system for energy dispersive X-ray spectroscopy (EDX) with high sensitivity. For sample preparation of the sensitive materials, the use of cryo argon ion polishing promises the fabrication of high-quality cross sections, through which a significantly increased informative value of the SEM images is achieved in many samples or an evaluation is made possible at all. Using a cryopreparation unit, it will be possible to examine samples that are not stable at room temperature by cooling them with liquid nitrogen during preparation and examination. At the same time, freezing and thawing processes can be simulated, examined and monitored using SEM imaging.The requested system complements the equipment already available at Leibniz University Hannover. In particular, cryo SEM examinations and sample preparation using argon ion polishing are made possible for the first time.The recurring research tasks to be processed with the requested system include the evaluation of fiber surfaces, nonwovens, interface qualities and failure mechanisms in the development of fiber-reinforced plastics. For the evaluation of the fiber-matrix adhesion, in addition to fracture surface analysis, the cross section analysis using argon ion polishing will be used.When developing new recycling approaches for plastics, SEM investigations serve to analyze the structure of complex materials (including multi-layer composites) in order to develop suitable processing strategies based on them. SEM analyzes of the intermediate and end products provide information about the influence of processing steps on the material characteristics.In projects on the marine degradability of plastics, test specimens from field tests are to be examined, which often show significant biological coverage. With argon ion polishing, cross sections can be produced here that do not destroy the biofilms. This makes it possible to evaluate the degradation mechanisms inside the specimen.In the research field of cryotechnology, the influences of the process parameters of freezing and thawing processes of biosamples (suspended cells, tissue) as well as combination products (polymeric carrier structures with cells / tissue from tissue engineering and regenerative medicine) are to be investigated. The cryopreparation unit enables the typical process steps to be simulated. At the same time, structural influences can be quantified with a resolution that is superior to the cryo microscopy available at the IMP.