mosaic crystal

Viable tobacco mosaic crystals have been found dating from the sixteenth century.

When the crystallites are mostly ordered with just some random spread of orientations, one has a mosaic crystal.

An important application of mosaic crystals is in monochromators for x-ray and neutron radiation.

Pyrolitic graphite forms mosaic crystals with controlled mosaicities up to a few degrees.

The spectrometer has no collimators and uses a graphite mosaic crystal as an analyser.

A mosaic crystal is supposed to consist of smaller crystalline units that are somewhat misaligned with respect to each other.

I. Mosaic crystals of zinc.

In 1968 he published a theory that took into account both extinction and the Borrmann effect for X-ray diffraction in mosaic crystals.

In 1997, he published a generic solution of the Darwin-Hamilton equations that provide an approximative description of multiple Bragg reflection by a mosaic crystal.

A mosaic crystal is an idealized model of an imperfect crystal, imagined to consist of numerous small perfect crystals (crystallites) that are to some extent randomly misoriented.

Pyrolitic graphite (PG) can be produced in form of mosaic crystals (HOPG: highly ordered PG) with controlled mosaicity of up to a few degrees.

To describe diffraction by a thick mosaic crystal, it is usually assumed that the constituent crystallites are so thin that each of them reflects at most a small fraction of the incident beam.

During normal growth, they may acquire defects from distorted internal structure between mosaic crystals, suffer omission defects where grounds of atoms or molecules are missing from lattice sites, have charge displacements (for example where there are abnormally ionized atoms), or undergo mechanical damage such as formation of distorted surfaces and cracks.