Moiré Fringes and/or Translation-Fault Fringes?

Ohler, M.; Härtwig, J.; Prieur, E.

doi:10.1107/s0108767396013438

Cited by 39 publications

(10 citation statements)

References 12 publications

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“…The origin of the observed fringe systems is still unclear although the possibilities seem to be limited to (a) Moire´fringes due to the superposition in the direction of the diffracted beam of different crystal volumes having slightly different misalignment or lattice parameters [27] or (b) Pendello¨sung fringes due to the presence of wedge-shaped crystal volumes [28].…”

Section: Discussionmentioning

confidence: 99%

Topography and high resolution diffraction studies in tetragonal lysozyme

Otálora

García‐Ruiz

Gavira

et al. 1999

Journal of Crystal Growth

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Two complementary approaches are used to enhance the usefulness of X-ray topographies obtained from protein crystals. First, the use of thin plate-like crystals in conjunction with a high intensity, collimated and small source size synchrotron beam produces a large beneficial effect on the level of detail and contrast of topographies for the quantification of local misalignment in the crystal lattice. Second, the recording of topography series along the rocking curve of a diffraction peak is proposed as a technique to combine the benefits of both rocking curves and topographies and produce very detailed data ("rocking maps") on the spatial distribution of lattice misalignments and mosaic spread ("local rocking curves"). The most important crystal features controlling the observed contrast are growth sectors and inter-sector boundaries, clearly observed in the topographies. Systems of parallel fringes are observed in many of the topographies. Two alternative explanations for these fringes are discussed: (a) as moire´interference fringes or (b) as Pendello¨sung fringes in a wedge shaped crystal volume. In both cases, growth sectors play a central role in the physics of fringe generation. Many observations suggest the presence of a relatively large component of dynamical diffraction in these crystals; the consequences of this new scenario are discussed.

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Section: Discussionmentioning

confidence: 99%

Topography and high resolution diffraction studies in tetragonal lysozyme

Otálora

García‐Ruiz

Gavira

et al. 1999

Journal of Crystal Growth

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“…Simon & Authier (1968), and Gerward (1973) reported moiré fringes observed in ion-implanted silicon crystals. Although referred to their observed fringes as 'translation fault' fringes , Ohler et al (1997) later explained that they are essentially moiré fringes. Moiré fringes observed with a monolithic type bicrystal, prepared by making a saw cut in a single crystal, were reported by Hashizume et al (1972) and Tanemura & Lang (1973).…”

Section: Introductionmentioning

confidence: 99%

Theoretical study of the properties of X-ray diffraction moiré fringes. I

Yoshimura

2015

Acta Cryst Sect A

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A detailed and comprehensive theoretical description of X-ray diffraction moiré fringes for a bicrystal specimen is given on the basis of a calculation by planewave dynamical diffraction theory. Firstly, prior to discussing the main subject of the paper, a previous article [Yoshimura (1997). Acta Cryst. A53, 810-812] on the two-dimensionality of diffraction moiré patterns is restated on a thorough calculation of the moiré interference phase. Then, the properties of moiré fringes derived from the above theory are explained for the case of a plane-wave diffraction image, where the significant effect of Pendellö sung intensity oscillation on the moiré pattern when the crystal is strained is described in detail with theoretically simulated moiré images. Although such plane-wave moiré images are not widely observed in a nearly pure form, knowledge of their properties is essential for the understanding of diffraction moiré fringes in general.

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“…Consequently, the misaligned growth sectors could produce some degree of stress inside the crystal lattice and wedge-shaped volumes. Therefore, the origin of the observed fringes is considered to be due to Moire fringes due to the superposition in the direction of the diffracted beam of different crystal volumes having slightly different misalignment or lattice parameters 37 or Pendellösung fringes due to the presence of wedge-shaped crystal volumes. 38 For the orthorhombic form, as shown in Figure 3, not only dislocation lines but also growth sector boundaries (marked OSB) were clearly observed.…”

Section: Resultsmentioning

confidence: 99%

Observation of Clear Images of Dislocations in Protein Crystals by Synchrotron Monochromatic-Beam X-ray Topography

Koishi

Ohya

Mukobayashi

et al. 2007

Crystal Growth & Design

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Crystal defects, especially dislocations, in hen egg-white lysozyme crystals that have multiple polymorphisms, for example, tetragonal, orthorhombic, monoclinic forms, etc., were investigated by means of synchrotron monochromatic-beam X-ray topography. The observed topographic images of dislocations were much clearer compared to those of any protein crystals that have been reported so far. It was demonstrated that millimeter-size crystals larger than extinction lengths for X-ray topographic reflections are required to obtain clear images, that is, direct images, for protein crystals. In addition, the weak-beam technique was found to be useful for obtaining clearer images. Straight, curved, and loop-type dislocations were clearly resolved on the topographs. This shows that dislocations observed in common inorganic crystals and organic crystals of small molecules can also be introduced even into protein crystals. The shape and configuration of dislocations strongly depended on the crystal form. This suggests that the growth mechanisms in the different crystal forms studied may differ. X-ray topography provides a useful tool for the characterization of protein crystal dislocations.

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Moiré Fringes and/or Translation-Fault Fringes?

Cited by 39 publications

References 12 publications

Topography and high resolution diffraction studies in tetragonal lysozyme

Topography and high resolution diffraction studies in tetragonal lysozyme

Theoretical study of the properties of X-ray diffraction moiré fringes. I

Observation of Clear Images of Dislocations in Protein Crystals by Synchrotron Monochromatic-Beam X-ray Topography

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