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Contrast transfer function
About: Contrast transfer function is a research topic. Over the lifetime, 934 publications have been published within this topic receiving 26533 citations.
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8 citations
01 Aug 1992
8 citations
21 Feb 2004-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, a program for the numerical calculation of the electrostatic potential can use these integrals to calculate the C s, C c and the slope aberrations of a low voltage foil corrector.
Abstract: Foil aberration correctors make use of a transparent foil to correct for the spherical and chromatic aberration of electron lenses. The low-voltage foil corrector is a novel type, in which the electrons are retarded to almost 0 eV at the foil. For designing a system with this corrector, analytical expressions for the aberrations are required. Such aberration integrals allow combinations of the corrector with other lenses to be calculated, even if the fields overlap. Also many different configurations can be calculated within a reasonable time. Most existing aberration integrals for foil correctors are not suitable because of an integration by parts that had been applied to them, such to obtain expressions without the fourth derivative of the axial potential. This simplification is not allowed when the electron energy approaches zero and is not necessary nowadays because the fourth derivative can be calculated accurately. Additionally, for a characterization of the corrector independent of the probe forming system, the aberration coefficients are less suitable and the geometrical and chromatic slope aberrations must be derived. In this paper, integrals have been obtained that describe correctly the spherical and chromatic aberration correction for the low voltage foil corrector. A program for the numerical calculation of the electrostatic potential can use these integrals to calculate the C s , C c and the slope aberrations. The results show that the low-voltage foil corrector can correct for both the spherical and chromatic aberration simultaneously.
8 citations
TL;DR: In this paper, a method for quantifying the information contained in high-resolution electron micrographs by the measurement of the intensity of reflections in diffractograms is presented, where the imaging parameters are determined simultaneously with the amplitudes and phases of the Fourier components of the exit-surface wave function.
8 citations
TL;DR: The performance of many electron optical instruments is fundamentally limited by the dimensions of the focused probe and this is true of both the scanning electron microscope and the scanning transmission electron microscope.
Abstract: SUMMARY
The performance of many electron optical instruments is fundamentally limited by the dimensions of the focused probe. This is true of the scanning electron microscope and the scanning transmission electron microscope and, by inference, it may affect the transmission electron microscope. There has been very little improvement over the past few years and it seems reasonable to look for the explanation. It is possible to arrive at some simple expressions for the limiting performances of conventional instruments in a way that is independent of the design details and depends upon practical limits of field strength. Experiment and theory also appear to be in agreement with the fact that the limit for high-voltage instruments has been reached, although there is still room for improvement for low voltages.
8 citations