“Ghost Feature” in 2-D Diffractograms
- Practical Electron Microscopy and Database -
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Figures 4168 (a) and (b) shows CTFs and diffractograms obtained based on two different TEM systems. The 1-D diffractograms (intensity spectra) cannot simply be said to be equal to the absolute value of CTF, but in “ideal” condition they are equal. The profiles were obtained by computing for zero beam convergence at Scherzer defocus. The “Ghosts” in the circular 2-D diffractograms were aliasing from sub-sampling of the fine rings. In Figure 4168 (a), the transfer drops to 1/e2 at 1.05 Å, while in Figure 4168 (b) the transfer is still 50% at 1.05 Å and falls to 1/e2 at 0.8 Å, resulting higher spatial resolution.

CTFs and diffractograms

Figure 4168. (a) and (b) CTFs and diffractograms obtained based on two different TEM systems [1].

 

 

[1] M. A. O’Keefe, C. J. D. Hetherington, Y. C. Wang, E. C. Nelson, J.H. Turner, C. Kisielowski, J. -O. Malm, R. Mueller, J. Ringnalda, M. Pane, and A. Thust, Sub-Ångstrom high-resolution transmission electron microscopy at 300 keV, Ultramicroscopy 89 (2001) 215–241.

 

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