METHOD OF DETERMINING MOSAIC STRUCTURE OF CRYSTAL Russian patent published in 2009 - IPC G01N23/20 

FIELD: physics.

SUBSTANCE: invention can be used to determine mosaic structure of a crystal. A sample is put into a vacuum chamber. The sample is exposed to a narrow beam of X-ray radiation and the characteristic value of mean mosaic angle of the analysed sample η₀ is evaluated from the characteristic width of the diffraction peak. The mosaic structure of the crystal is determined from distribution functions of micro-units of the mosaic crystal from mosaic angles η_⊥,η_// in two mutually perpendicular directions, for which the sample is put into a vacuum target chamber, which is fitted with a goniometre, exposed to a stream of broadband X-ray radiation, value of scattering angle of radiation χ is determined such that, Bragg frequency ω_g=g/2sin(χ/2), in the neighbourhood of which is concentrated the radiation spectrum scattered by the crystal plane, recorded by the reciprocal lattice vector g, falls on the most flat section of the spectrum of primary radiation. After evaluation of the mean mosaic angle η₀ a radiation detector with angular dimension Δϑ is fitted, where the angular dimension is equal to the ratio of the dimension of the detector to the distance between the detector and the target, at a distance which satisfies the equation Δϑ=η₀. Using the goniometre, the orientation dependence of the number of scattered quanta N_g((φ') is determined, where φ' is angle of deviation of the crystal from the position of Bragg resonance, and the distribution function of micro-units of the mosaic crystal in a fixed plane is determined. The crystal is then turned 90 degrees about the average direction of the reciprocal lattice vector and orientation dependency is measured again using the goniometre, which enables determination of the distribution function of micro-units of the mosaic crystal in the perpendicular plane.

EFFECT: possibility of determining a two-dimensional distribution function of micro-units of a mosaic crystal from mosaic angles.

5 dwg