Motoki Sohei, Kaneko Takeshi, Aoyama Yoshitaka, Nishioka Hideo, Okura Yoshihiro, Kondo Yukihito, Jinnai Hiroshi
Electron Optics Division, JEOL Ltd., 3-chome Akishima, Tokyo, Japan.
J Electron Microsc (Tokyo). 2010 Aug;59 Suppl 1:S45-53. doi: 10.1093/jmicro/dfq030. Epub 2010 Jun 29.
It has been shown that scanning transmission electron microtomography (STEMT) is quite effective for observing specimens with thicknesses on the order of micrometers in three dimensions (3D). In STEMT, the specimen is scanned using a focused electron beam, and the electrons from the convergence point are detected at the detector placed at a certain detection angle. Until recently, a wide detection angle corresponding to the mode often called the dark-field (DF) mode was mainly used. Although the detection angle can vary and is one of the crucial experimental factors in STEMT, its effect on 3D reconstruction has never been discussed from either an experimental or a theoretical viewpoint. Moreover, the effectiveness of another mode of electron tomography, transmission electron microtomography (TEMT), is not clear. In the present study, a polymeric specimen, an acrylonitrile butadiene styrene resin, with a thickness of ~1 mum and a fixed volume was observed using three different modes, namely, TEMT, small detection-angle STEMT referred to as bright-field STEMT, and DF-STEMT, in order to examine their advantages and disadvantages by observing multiple scattering of electrons inside the specimen.
研究表明，扫描透射电子显微断层扫描（STEMT）在三维（3D）观察厚度为微米级的标本方面非常有效。在STEMT中，使用聚焦电子束对标本进行扫描，并在以特定检测角度放置的探测器处检测来自会聚点的电子。直到最近，主要使用对应于通常称为暗场（DF）模式的模式的宽检测角度。尽管检测角度可以变化，并且是STEMT中的关键实验因素之一，但其对3D重建的影响从未从实验或理论角度进行过讨论。此外，另一种电子断层扫描模式，即透射电子显微断层扫描（TEMT）的有效性尚不清楚。在本研究中，使用三种不同模式观察了厚度约为1μm且体积固定的聚合标本，即丙烯腈-丁二烯-苯乙烯树脂，这三种模式分别是TEMT、称为明场STEMT的小检测角度STEMT和DF-STEMT，以便通过观察标本内部电子的多重散射来检验它们的优缺点。
