Automated Phase Plate Application In Transmission Electron Microscopy

By Marco Oster

Transmission electron microscopy is an essential tool to determine the structure of biological and material-science samples. A majority of the studied specimen are phase objects, i.e. they impose a small distortion on the phase on the traversing electron wave. To visualize this signal, conventional transmission electron microscopy needs to apply intended lens aberrations, which results in distorted images. Phase plate microscopy offers an alternative possibility to generate phase contrast without relying on the lens aberrations. However, the delicate alignment of the phase plates and their quick degeneration prevent their routine application. In this work, approaches for automating the phase plate alignment are developed. To further improve the applicability, different means to reduce the so-called cut-on effect are evaluated. For that, the characteristics of a prototype instrument especially constructed to solve the cut-on problem are assessed and the properties of a new dynamic imaging mode examined in a theoretical study and by simulation. The applicability of the approach is demonstrated on beam-sensitive samples using the developed automation routines. Die Transmissionselektronenmikroskopie dient als essentielles Werkzeug der Strukturaufkl rung biologischer und materialwissenschaftlicher Systeme. Ein Gro teil der dort untersuchten Proben sind Phasenobjekte, d.h. ihre Interaktion mit der durchlaufenden Elektronenwelle bewirkt eine Phasen nderung selbiger. Zur Sichtbarmachung dieses Signals werden in der konventionellen Transmissionselektronenmikroskopie Linsenaberrationen benutzt, wobei das entstehende Bild von entsprechenden Abbildungsfehlern behaftet ist. Phasenplattenmikroskopie bietet eine alternative M glichkeit der Kontrasterzeugung, ohne dabei Linsenaberrationen zu ben tigen. Jedoch verhindern sowohl die zur Anwendung notwendigen diffizilen Bedientechniken, als auch die gro e Empfindlichkeit heutzutage verf gbarer Phasenplattensysteme bisher

• Format: Paperback
• Language: English
• ISBN: 3736995628
• ISBN13: 9783736995628
• Release Date: June 2017
• Publisher: Cuvillier
• Length: 208 Pages
• Weight: 0.56 lbs.
• Dimensions: 0.4" x 5.8" x 8.3"