1 April 1993 Another definition of resolution for the electron microscope
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Proceedings Volume 1982, Photoelectronic Detection and Imaging: Technology and Applications '93; (1993); doi: 10.1117/12.142057
Event: Photoelectronic Detection and Imaging: Technology and Applications '93, 1993, Beijing, China
Abstract
Resolution of an electron microscope is often estimated by adding the aberrations of the optical system in quadrature with the diffraction disk and the source size. It is known that this is not particularly accurate and that it is not really theoretically justified. In the case of large aberrations, such as when the beam limiting aperture angle is large, there is the possibility of ambiguity in the estimate of system performance because the optical transfer function may have significant structure. It was shown by Fellgett and Linfoot together, and by Linfoot alone, that it is possible to define the information transmitting capacity of an optical system in terms of the optical transfer function. If one makes use of their result then the resolution of an optical system can be defined by comparing it with the resolution of a diffraction limited system having the same information transmitting capacity. The method gives results that agree well with measurements made on a high resolution scanning electron microscope. In addition, it emphasizes the importance of the current density distribution for understanding the performance on an electron (or ion) optical instrument.
© (1993) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jon H. Orloff, "Another definition of resolution for the electron microscope", Proc. SPIE 1982, Photoelectronic Detection and Imaging: Technology and Applications '93, (1 April 1993); doi: 10.1117/12.142057; https://doi.org/10.1117/12.142057
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KEYWORDS
Optical transfer functions

Spatial frequencies

Diffraction

Spatial resolution

Electron microscopes

Ion beams

Ions

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