Nanosecond time-resolved investigations using the in situ

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• 作者：Thomas LaGrange ; Geoffrey H. Campbell ; B.W. Reed ; Mitra Taheri ; J. Bradley Pesavento ; Judy S. Kim ; Nigel D. Browning
• 关键词：Ultrafast electron diffraction ; Time resolved electron microscopy ; Catalysis ; Martensitic phase transformations
• 刊名：Ultramicroscopy
• 出版年：2008
• 出版时间：October 2008
• 年：2008
• 卷：108
• 期：11
• 页码：1441-1449
• 全文大小：1781 K

文摘

Most biological processes, chemical reactions and materials dynamics occur at rates much faster than can be captured with standard video rate acquisition methods in transmission electron microscopes (TEM). Thus, there is a need to increase the temporal resolution in order to capture and understand salient features of these rapid materials processes. This paper details the development of a high-time resolution dynamic transmission electron microscope (DTEM) that captures dynamics in materials with nanosecond time resolution. The current DTEM performance, having a spatial resolution <10 nm for single-shot imaging using 15 ns electron pulses, will be discussed in the context of experimental investigations in solid state reactions of NiAl reactive multilayer films, the study of martensitic transformations in nanocrystalline Ti and the catalytic growth of Si nanowires. In addition, this paper will address the technical issues involved with high current, electron pulse operation and the near-term improvements to the electron optics, which will greatly improve the signal and spatial resolutions, and to the laser system, which will allow tailored specimen and photocathode drive conditions.