Accession Number : ADD014549

Title :   High Resolution Technique and Instrument for Measuring Lattice Parameters in Single Crystals.

Descriptive Note : Patent Application, Filed 28 Feb 90,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Fatemi, Mohammad

Report Date : 28 Feb 1990

Pagination or Media Count : 39

Abstract : A method of measuring the lattice parameter in an unknown single crystal by comparing its diffraction angle to a standard single crystal, on a double-crystal diffractometer is disclosed. The method comprises several steps including mounting the unknown and standard crystals on a mounting block of the second stage of a double-crystal diffractometer such that a tilt axis of the crystal surface is in line with an x-ray beam and the azimuth axis of the second stage crystal mount, rotating the mounting block until the normals of the crystals have equal vertical components, tilting the crystals about the azimuth axis of the mounting block until the crystal normals lie in the horizontal plane in line with the x-ray beam, such that the same point on the crystal surface remains fixed in the x-ray beam, sequentially measuring the angle of the sharpest diffraction peak from each crystal while moving the crystals laterally across the beam, rotating the crystal mounting block assembly by 180 degrees about the azimuth axis while maintaining the relative tilt between the two wafers, such that the same area of the crystal surface remains in the x-ray beam during the 180 degrees rotation, sequentially measuring the angle of sharpest diffraction peak of both crystals after rotation, and calculating the diffraction angle of the unknown crystal from the standard crystal diffraction angle. Patent Applications.

Descriptors :   *PATENT APPLICATIONS, *SINGLE CRYSTALS, ANGLES, ASSEMBLY, AZIMUTH, CRYSTALS, DIFFRACTION, HIGH RESOLUTION, HORIZONTAL ORIENTATION, MOUNTS, PEAK VALUES, SURFACES, TILT, VERTICAL ORIENTATION, WAFERS, X RAYS

Subject Categories : Crystallography
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE