Practical considerations for high spatial and temporal resolution dynamic transmission electron microscopy
Autor: | Jeffrey D. Colvin, Alan M. Frank, W.J. DeHope, Wayne E. King, David Gibson, Michael R. Armstrong, Thomas LaGrange, Ken Boyden, Fred Hartemann, Ben J. Pyke, Ben Torralva, Geoffrey H. Campbell, Bryan W. Reed, Nigel D. Browning, Brent C. Stuart, R. M. Shuttlesworth, Judy S. Kim |
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Rok vydání: | 2007 |
Předmět: |
Microscope
Materials science business.industry Resolution (electron density) Pulse duration Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials law.invention Field electron emission Optics law Temporal resolution Secondary emission High-resolution transmission electron microscopy business Instrumentation Image resolution |
Zdroj: | Ultramicroscopy. 107:356-367 |
ISSN: | 0304-3991 |
Popis: | Although recent years have seen significant advances in the spatial resolution possible in the transmission electron microscope (TEM), the temporal resolution of most microscopes is limited to video rate at best. This lack of temporal resolution means that our understanding of dynamic processes in materials is extremely limited. High temporal resolution in the TEM can be achieved, however, by replacing the normal thermionic or field emission source with a photoemission source. In this case the temporal resolution is limited only by the ability to create a short pulse of photoexcited electrons in the source, and this can be as short as a few femtoseconds. The operation of the photo-emission source and the control of the subsequent pulse of electrons (containing as many as 5 x 10(7) electrons) create significant challenges for a standard microscope column that is designed to operate with a single electron in the column at any one time. In this paper, the generation and control of electron pulses in the TEM to obtain a temporal resolution10(-6)s will be described and the effect of the pulse duration and current density on the spatial resolution of the instrument will be examined. The potential of these levels of temporal and spatial resolution for the study of dynamic materials processes will also be discussed. |
Databáze: | OpenAIRE |
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