Practical Electron Microscopy and Database

Spherical aberration coefficient (C_s) defines the quality of objective lens. The accurate determination of the spherical aberration coefficient C_s is very important to many applications of EM techniques, such as electron holography [1,2], image processing and deconvolution [3], and electron crystallography of proteins [4].

The typical spherical aberration coefficients for uncorrected electron microscopes operating at 200 kV are 0.5–2 mm.

The values of Δf (defocus value), C_s (spherical aberration coefficients, listed in page4579), and D (standard deviation of the Gaussian distribution of defocus due to the chromatic aberration) can be obtained by TEM image deconvolution.

1. Liehte, H., Parameters for high-resolution electron holography, Ultramicroscopy, 1993, 51, 15.
2. Peng, L.-M., Ren, G., Duan, X. F., Samplling theorem and digital electron microscopy, J. Chinese Electron Microscopy Society (in Chinese), 1996, 15(2-4), 117.
3. Li, F. H., Combination of high resolution electron microscopy and electron diffraction in crystal structure determination, J. Chin. Electr. Microsc. Soc., 1996, 1592-4, 143.
4. Baumeister, W., Typke, D., Electron Crystallography of Proteins, State of the Art and Strategies for the Future, MSA Bulletin, 1993, 23(1), 11.