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MIND MAP 2, Sharifah Azra Bt Abdul Kadir - Coggle Diagram

- - - - primary source:X ray
        
        X ray generation
        
        Process 2- Non- elastic excitation of core electrons
        
        Prosess 1 - Decelaration of electron in the metal target
        
        example of Xray spectrum
        
        Diffraction pattern of an Xray from a crystal
      - Secondary sources : Neutron, electron
      - von Laue (1912); Crystal as 3D diffraction gartings
      - Electron diffractions is used for surface study of materials
        
        short penetration power
        
        suitable for surface study of crystal , thin films and thin crystals
        
        de Broglie relation for e
      - Neutron diffraction is used for high precision study
        
        Neutron is used to study magnetic structure of materials - based on its magnetic moment
        
        Spectrum of slow neutron - radiation from a narrow wavelenght band selected using a monochromator
  - - - similar principle to multiple slit experiments
      - Constructive and destructive interference patterns depends on lattice spacing (d) and wavelenght and radiation (l)
      - By varying wavelenght and observing diffractions pattern , information about latice spacing is obtained.
    - - d spacing in different crystal systems
- - - - Bragg reflected ray
        
        When a crystal is bombarded with X-rays of a fixed wavelength (similar to spacing of the atomic-scale crystal lattice planes) and at certain incident angles, intense reflected X-rays are produced when the wavelengths of the scattered X-rays interfere constructively.
  - - - Laue Equations
        
        Ewald sphere and Reciprocal lattice
        
        The Ewaald construction is the way to draw bragg's lawa. Crystallographers use it to visualize which reciprocal lattice point will be in diffraction condidtion for a given orientation of the crystal.
- - - - A single crystal specimen in Bragg- Brentano diffractometer would produce only one family of peaks in the diffraction pattern
      - A polycrystalline sample should contain thousands of crystallites . Therefore, all possible diffraction peaks should be observed.
    - - Indexing the peeks
      - Absences due to lattice centering
  - - - To summarize The journey from the real lattice to the different pattern by Real lattice to real Crystal to Reciprocal lattice to Reciprocal crsytal to Diffration Pattern
- - - - Ewald construction diagram for crystal rotation technique
    - - Transmissin technique
        
        Film use for recording the diffraction pattern is placed behind the sample and records the fowrad diffracted ray
      - Reflected ray technique
        
        Film use for recording the diffraction pattern is placed between source and sample.
      - Calculating Laue's angle
      - Ewald Construction for laue tehnique
  - - - Solid crystals
      - Liquid or amorphous solid