Explain the construction and working of X-Ray diffractometer.

10.A] Explain the construction and working of X-Ray diffractometer.


10.A] Explain the construction and working of X-Ray diffractometer.
X-Ray diffractometer

Principle of X-Ray Diffractometer:
X-ray diffractometer is based on the principle of Braggs’ Law The constructive interference of monochromatic Xrays reflected by a crystalline sample is studied.

  • Construction of XRD
    • The main arrangements consist of X-Ray source, Specimen and Detector.
    • The X-ray radiation generated by an X-ray tube is collimated by passing through soller slits.
    • Soller Slits are the arrangement of closely spaced thin metal plates in parallel to prevent beam divergence.
    • A divergent X-ray beam from the soller slits strikes the specimen.
    • X-rays are diffracted by the specimen on the mount(turntable) and form a convergent beam at the receiving soller slits before they enter a detector.
    • The diffracted X-ray beam is passed through the monochromator before being received by the detector.
    • The monochromatic filter is used suppress wavelengths other than Kα radiation. • The detector and the turn-table are so coupled, if the crystal is rotated through an angle θ then the detector turns through an angle 2θ.
    • The reflected X-rays are collimated and manochromatic X-rays from the monochromator are collected by the detector.
    • The intensity of the reflected X-ray beam as a function of 2θ is recorded in a computer.
    • A plot of Intensity as a function of 2θ. thin-film XRD requires a parallel incident beam, not a divergent beam as in regular diffractometry.
    • The small glancing angle of the incident beam ensures that sufficient diffraction signals come from a thin film or a coating layer instead of the substrate.

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