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We developed a spot measurement tool to characterize rapidly arrays of diffraction spots that are characteristic of a single crystal, and to measure precisely the d-spacing values for individual spots.
Switch to diffraction mode. Adjust convergence angle (C3) within the limits given by the area you want to investigate. Focus the diffraction pattern with the intermediate lens (diffraction focus). Correct astigmatism. Block zero beam with the pointer. (You can damage the CCD)
In optics, the Arago spot, Poisson spot, or Fresnel spot is a bright point that appears at the center of a circular object's shadow due to Fresnel diffraction. This spot played an important role in the discovery of the wave nature of light and is a common way to demonstrate that light behaves as a wave.
29 de set. de 2022 · The chapter deals with indexing of spot-type diffraction patterns observed in high-voltage electron microscopes. Indexing of spot patterns is a special case of general problem of indexing single-crystal diffraction data, but it is often seen it as a separate field...
- Adam Morawiec
- nmmorawi@cyf-kr.edu.pl
The resolution limitations in microscopy are often referred to as the diffraction barrier, which restricts the ability of optical instruments to distinguish between two objects separated by a lateral distance less than approximately half the wavelength of light used to image the specimen.
When light passes through any size aperture (every lens has a finite aperture), diffraction occurs. The resulting diffraction pattern, a bright region in the center, together with a series of concentric rings of decreasing intensity around it, is called the Airy disk (see Figure 1).
In optics, the Airy disk (or Airy disc) and Airy pattern are descriptions of the best- focused spot of light that a perfect lens with a circular aperture can make, limited by the diffraction of light. The Airy disk is of importance in physics, optics, and astronomy .
