Spherical aberration coefficient (Cs) defines the quality of objective lens. The accurate determination of the spherical aberration coefficient Cs is very important to many applications of EM techniques, such as electron holography [1,2], image processing and deconvolution , and electron crystallography of proteins .
The typical spherical aberration coefficients for uncorrected electron microscopes operating at 200 kV are 0.5–2 mm.
The values of Δf (defocus value), Cs (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.