XRD is a rapid analytical technique primarily used for phase identification of crystalline material and can provide information on unit cell dimensions.

1. INSTRUMENTAL SEMINAR
X- RAY DIFFRACTION
Vimarsha V Bhatkalkar
1st Year PG Scholar
Department of Rasashastra & Bhaishajya Kalpana
KLE Shri BMK Ayurveda and Mahavidyalaya & Hospital
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2. CONTENTS
• Introduction
• Origin
• Objective
• Principles of XRD
• Working of XRD
• Unit
• Advantages
• Disadvantages
• Application in the field
• Summary
• Conclusion
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3. INTRODUCTION
• X-ray powder diffraction (XRD) is a rapid analytical technique primarily used for
phase identification of a crystalline material and can provide information on unit
cell dimensions.
• The analyzed material is finely ground, homogenized, and average bulk
composition is determined.
• X-ray diffraction is now a common technique for the study of crystal structures and
atomic spacing.
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4. ORIGIN
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1895
1914
1915
1953
Now
X-rays were discovered by Roentgen.
First diffraction pattern of a crystal was made by Kipping and Von Laue.
Theory to determine crystal structure from diffraction pattern was developed by Bragg.
DNA structure solved by Watson and Crick.
Diffraction improved by computer technology: methods used to determine atomic
structures and in medical applications.

5. OBJECTIVE
• To know about the X-ray diffraction machine.
• To understand the working pattern of the apparatus.
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6. PRINCIPLE
• X-ray diffraction analysis (XRD) is a technique used in
materials science to determine the crystallographic structure
of a material.
• XRD works by irradiating a material with incident X-rays
and then measuring the intensities and scattering angles of
the X-rays that leave the material.
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7. WORKING OF XRD
• First sample is formed and introduced or
mounted on tip of the needle by goniometer
process.
• Then monochromatic beam of X-ray is
bombarded on sample.
• The electron surrounding on the molecule
diffract as the X-ray hit them.
• Then diffracted rays reaches to film which is
connected to the detector.
• This forms a pattern and this type of pattern is
called the X-ray diffraction pattern.
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8. WORKING OF XRD
• The interaction of the incident rays with the sample produces constructive interference
(and a diffracted ray) when conditions satisfy Bragg's Law (nλ=2d sin θ).
(This law relates the wavelength of electromagnetic radiation to the diffraction angle and
the lattice spacing in a crystalline sample)
• The Bragg law is useful for measuring wavelengths and for determining the lattice
spacings of crystals.
• To measure a particular wavelength, the radiation beam and the detector are both set at
some arbitrary angle θ. The angle (bragg angle) is then modified until a strong signal is
received.
• The Bragg angle then gives the wavelength directly from the Bragg law. This is the
principal way to make precise energy measurements of X-rays and low-energy gamma
rays. 8

9. BRAGG’S LAW
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10. CONTD….
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λ is the wavelength of the x-ray,
d is the spacing of the crystal layers (path difference)
Ɵ is the incident angle (the angle between incident ray and the scatter plane), and
n is an integer (n=1,2..etc)

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12. COMPONENTS OF X-RAY
DIFFRACTION INSTRUMENTATION
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1. An X-ray tube
2. Sample holder
3. X-ray detector

13. INSTRUMENTATION
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• Radiation source
• Collimator
• Monochromator
a) Filter monochromator
b) Crystal monochromator
• Detectors
1. Photographic methods
2. Counter methods
a) Geiger muller tube counter
b) Proportional counter
c) Scintillation counter
d)Semi- conductor detectors

14. RADIATION SOURCE
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• X-ray tubes ( X-ray are generally produced in XRT)
• Radioisotopes
• Secondary fluorescent

15. COLLIMATOR
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• A device that is used for narrowing a beam of particles or waves
• Collimator makes random directional X-rays to be narrow and parallel.
• These are usually made up of tungsten, stainless steel or ceramics.
• Pitch ranges from 400 microns to 6 microns.

16. MONOCHROMATOR
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• A device that is used for removing unwanted radiation.
Types
Filter monochromator Crystal Monochromator
Made up of specialized material that absorb
unwanted radiation and passes the desired radiation
Examples: X-rays produced from molybdenum are
Monochromatized by zirconium filters.
These are the device that partially polarize a non
polarized X-ray beam on the basis of Bragg’s
diffraction.
Types:
1. Flat crystal
2. Curved crystal

17. DETECTORS
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X-rays can be detected using two types of detectors:
1. Photographic detectors
2. Counter detectors
a) Geiger muller tube counter
b) Proportional counter
c) Scintillation counter
d) Semi- conductor detectors

18. CONTD….
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Photographic detectors
• Photographic detectors are a plane or a cylindrical film which is used to determine
the position and intensity of x-rays.
• Cylindrical films are developed by exposing detectors to X-ray.
• The extent of developed film is expressed as density. Density of direct measurement
of x-ray energy causes blackening of photographic film.

19. CONTD….
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Geiger Muller Tube Counter
• It is composed of glass tube of about 19 mm in diameter.
• It is made up of Copper
• Along the axis of cylinder a thin metal wire of tungsten is tied. The cylinder and wire
are connected to an electrical voltage source.
• The tube is filled with gas usually Argon at a low pressure. A voltage is set up
between the cathode and anode.
• USE: The instrument is used for detecting and measuring ionizing radiation.

20. CONTD….
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Proportional Counter
• It is similar to Geiger Muller Counter.
• In this counter, a specialized circuit is connected to the tube so that X-rays of
particular energy can be measured.

21. CONTD….
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Scintillator Counter
• Scintillator is a material that exhibits the property of luminescence on excitement by
ionizing radiation.
• A Scintillator detector is a combination of scintillator with an electric light sensor
such as PMT (photomultiper tube).
• PMT absorbs the light emitted by the Scintillator and further re- emits in the form of
electrons.
• The re-emitted electrons result in an electrical pulse which provides information
about incident radiation particles.

22. CONTD….
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Semiconductor Detector
• Semiconductor Detector makes use of Indium antimonide or mercury cadmium
telluride.
• These detectors assists in promotion of X-rays through generated electrons into
conduction bands. Therefore the current generated is a direct measurement of X-rays
intensity.

23. SAMPLE COLLECTION
AND PREPARATION
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• Within a cathode ray tube, X-rays are produced by heating a filament to produce electrons, applying a
voltage to accelerate the electrons toward a target, and then bombarding the target material with
electrons.
• Typical X-ray spectra are generated when electrons have enough energy to remove the target material's
inner shell electrons. These spectra are made up of multiple components.
• The sample is exposed to these collimated X-rays. The intensity of the reflected X-rays is recorded
while the sample and detector are rotated.
• Constructive interference and the appearance of a peak in intensity happen when the incident X-rays'
geometry meets the requirements of Bragg's law and impacts the sample.
• Then, a detector records and processes this X-ray signal and converts the signal to a count rate which is
potrayed in a device such as a printer or computer monitor.

24. APPLICATIONS
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• Helps to identify unknown crystalline materials (e.g. minerals, inorganic compounds).
• Characterization of crystalline materials.
• Identification of fine-grained minerals such as clays and mixed layer clays that are difficult to determine
optically.
• Determination of unit cell dimensions.
• Measurement of sample purity.
• XRD is used to test the metals without removing the part from its position and without weakening it.
• Helps to determine the particle size

25. STRENGTH OF XRD
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• Powerful and rapid (< 20 min) technique for identification of an unknown mineral.
• In most cases, it provides an unambiguous mineral determination.
• Minimal sample preparation is required.
• XRD units are widely available.
• Data interpretation is relatively straight forward.

26. LIMITATIONS OF XRD
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• It cannot identify the amorphous materials.
• Does not give information on profile depth.
• It is a bulk technique requiring a large analysis volume and a large
minimum spot size.
• Tedious and time consuming.

27. COST
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Price in India: Rs. 1000- 10000

28. RESEARCH WORKS
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1. Preparation and physico chemical analysis of Ajasthi and Mrigashringa Bhasma (Dr.Harshitha M,
Guided by: Dr. R. S Hiremath)
 XRD of Ajasthi and Mrigashringa bhasma shows Calcium and Phosphorous peaks.
2. Screening of free radical scavenging activity and immuno-modulatory effect of samaguna
gandhakajeerna Rasasindhura (Dr.Veena B Kupati, Guided by Dr. P G Jadar)
 XRD – peaks of Rasasindhura are identical with the cinnabar i.e HgS. The particles are hexagonal in
structure.
3. Screening of free radical scavenging activity and immune modulatory effect of mukta (freshwater
cultured pearl) Bhasma (Dr. Poornima Tukanatti, Guided by Dr.P G Jadar)
 XRD report showed major peaks of CACO3 in aragonite form in shodhita mukta where as in mukta
Bhasma, major peaks of CACO3 in calcite form were found.

29. CONCLUSION
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• X-ray beam hits a crystal, scattering the beam in a manner characterized by the atomic
structure.
• Scientific validation of bhasma are done.
• Bio-molecules structures can be analyzed by x-ray diffraction, such as DNA and
proteins.
• This will be useful in the future for combining knowledge from physics, chemistry,
and biology.

30. THANK YOU
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