98:"Chromatic and spherical aberration are unavoidable errors of the space charge-free electron lens. In principle, distortion (strain and twist) and (all types of) coma can be eliminated. Due to the inevitability of spherical aberration, there is a practical, but not a fundamental, limit to the resolving power of the electron microscope."
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The resolution limit provided by
Scherzer's theorem can be overcome by breaking one of the above mentioned three conditions. Giving up rotational symmetry in electronic lenses helps in correcting spherical aberrations. A correction of the chromatic aberration can be achieved with time-dependent, ie
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He showed that under these conditions the aberrations that emerge degrade the resolution of an electron microscope up to one hundred times the wavelength of the electron. He concluded that the aberrations cannot be fixed with a combination of rotationally symmetrical lenses.
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Scherzer himself experimented with space charges (eg with charged foils), dynamic lenses, and combinations of lenses and mirrors to minimize aberrations in electron microscopes.
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Scherzer, Otto (1947). "Sphärische und chromatische
Korrektur von Elektronenlinsen".
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Schönhense, G. (2006). "Time-Resolved
Photoemission Electron Microscopy".
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for electromagnetic potentials assuming the following conditions:
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Proceedings of the 2005 Particle
Accelerator Conference
314:. Springer Science & Business Media. p. 237.
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High-Resolution
Imaging and Spectrometry of Materials
268:"Otto Scherzer. The father of aberration correction"
103:non-static, electromagnetic fields (for example in
82:electromagnetic fields are rotationally symmetric,
214:"Aberration Correction in Electron Microscopy"
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96:In his original paper, Scherzer summarized:
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331:Practical Electron Microscopy and Database
177:Advances in Imaging and Electron Physics
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297:Handbook of Charged Particle Optics
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189:10.1016/S1076-5670(05)42003-0
22:is a theorem in the field of
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299:. CRC Press. p. 234.
295:Orloff, Jon (June 1997).
229:10.1109/PAC.2005.1590354
37:found in 1936 that the
134:Zeitschrift für Physik
39:electromagnetic lenses
105:particle accelerators
71:are always positive.
62:chromatic aberration
51:spherical aberration
43:electron microscopes
41:, which are used in
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223:. pp. 44–48.
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183:: 159–323.
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371:Category
60:and the
336:5 April
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142:Bibcode
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353:Optik
271:(PDF)
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