X-rays were discovered in 1895 by Wilhelm Röntgen. X-rays are produced when high velocity electrons hit a metal target, knocking electrons out of inner shells of atoms within the target. As outer electrons fall into these vacancies, characteristic X-rays are emitted with energies specific to the element. X-ray diffraction methods like Bragg's law are used to analyze crystal structures of materials by detecting the angles and intensities of diffracted X-ray beams. Common applications include determining structures of polymers, particle sizes, and states of materials.

1. INTRODUCTION
X –RAYS: The X-ray region of electromagnetic spectrum
consists of shortest wavelength in the region of about 0.1 to
100AO
 For analytical purposes ,the range of 0.7 to 2.0AOis mostly
used.
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2. Radiotherapy
X-ray fluorescence
method
X-ray diffraction (or)
crystallography
X-ray absorption (or)
radiography
CLASSIFICATION
OF X-RAY
METHODS
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3. DISCOVERY
 X-rays were discovered by W.C.Rontgen is a german
physicist in 1895.
 For his work Rontgen awarded the first ever Nobel prize
for physics in 1901
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4. ORIGIN OF X-RAYS
 X-rays are generated when high velocity electrons impinge
on a metal target .
 The process of producing X-rays may be visualized in
terms of Bohr’s theory of atomic structure.
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5.  Whenever a fast moving electron impinges on an atom, it
may knock out an electron completely from one of the
inner shells of that atom.
 Following the loss of inner-shell electron one of the outer
electrons will fall in to the vacated orbital ,by the emission
of x-rays.
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6.  The energy of the emitted X-ray photon is equal to the
difference in energy between two levels involved.
E = E2-E1
 E2 and E1 are the final and initial energies which are
emitted from L and K shells respectively
 If the vacancy produced in the K-shell is filled by the
electron from L-shell, the radiation is called Kὰ .
 Electron from M-shell it is called Kβ.
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7.  The frequency of emitted radiation is given by
ϑ= Z² (2∏2me/h3)(1/N1
2 –1/N2
2 )
Z = Atomic number of an atom
m = mass of the electron
e = charge of the electron
h = plank's constant
N1 , N2 =1 & 2 for K&L shell
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8. TYPES OF RADIATION
1) BREHMSSTRAHLUNG (OR) BRAKING RADIATION:
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9. 2) CHARACTERISTIC X-RADIATION:
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10. X-RAY DIFFRACTION
INTRODUCTION
THEORY
INSTRUMENTATION
METHODS OF X –RAY
DIFFRACTION
APPLICATIONS
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11.  In 1912 von Laue placed a crystal of copper sulphate
between a white x-ray source and photographic plate
 The resulting photograph observed here:
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12. THEORY
ABSORPTION
DIFFRACTION
FLOUROSENCE
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13. DIFFRACTION
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14. BRAGG’S LAW
 Bragg’s equation is n=2dsinө
 Constructive interference occurs only when
 n=AB+BC
 AB=BC
 n=2AB
 Sinө=AB/d
 n=2dsinө
 =2dhklsinөhkl
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15. IN PHASE OUT OF PHASE
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16. INSTRUMENTATION
GENERATION OF X-RAYS
COLLIMATOR
MONOCHROMATOR
DETECTORS
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17. GENERATION OF X-RAYS
 X-rays are generated when high velocity of electrons
impinge on a metal target.
 Approximately 1% of total energy of electron beam is
converted in to x –radiation.
 Two type of devices are used for generating x-rays
1) X-ray tube
2) Synchrotron radiation
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18.  X-ray tubes:
Side window tube
End window tube
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19. Synchrotron radiation
 Synchrotron radiation is emitted by electron and positrons
travelling at near light speed in circular storage ring.
 Powerful sources which are thousands to millions of times
more intense than x-ray tubes.
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20. COLLIMATOR
 The x-rays produced by the target material are randomly
directed.
 In order to get a narrow beam of x-rays ,they are allowed to
pass through a collimator which consist of two sets of
closely packed metal plates separated by a small gap.
 The collimator absorbs all the x-rays except the narrow that
passes between the gap.
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21. MONOCHROMATORS
 Mainly two types:
a)FILTERS: It is a window of material that absorbs
undesirable radiation but allows the radiation of wave to
pass.
e.g. :Zirconium filter
 which is used for molybdenum radiation.
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22. some more examples of beta filters:
b)Crystal monochromators
1)Flat crystal monochromator
2)Curved crystal monochromator
TARGET
ELEMENT
ß-FILTERS THICKNESS %LOSS IN K∞
INTENSITY
Co Fe 0.012 39
Cu Ni 0.015 45
Fe Mn 0.011 38
Mo Zr 0.081 57
Ni Co 0.013 42
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23.  CRYSTAL MONOCHROMATOR: The beam is split into
component wavelength by the crystal line material such
material is called as Analyzing crystal.
 Crystals used in monochromators are sodium chloride,
lithium fluoride, quartz etc.
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24. DETECTORS
1) photographic method
2)counter methods
a) Geiger - Muller tube method
b) proportional counter
c) scintillation detector
d) solid-state semiconductor detector
e)semi conductor
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25. PHOTOGRAPHIC METHOD
 PRINCIPLE :
By using plane or cylindrical film
Developing the film
 D=log Io/I
D is the total energy
Measured by using densitometer
 USES: For diffraction studies
For quantitative measurement
 DIS ADVENTAGES: Time consuming
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26. SCINTILLATION DETECTOR
 Its mainly contains a large crystal of
sodium iodide activated with small
amounts of thallium.
 They convert incident x-rays in to visible
light which is detected by photo
multiplier tube.
 e.g. for crystals :
sodium iodide , anthracene,
naphthalene ,p- terpenol in xylene.
 Used for short wavelengths
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27. PROPORTIONAL COUNTER METHOD:
 It is filled with heavier gas like xenon ( or) krypton
it is preferred because it is easily ionized.
 More efficiency and sensitive
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28. GIEGER MULLER COUNTER
 PRINCIPLE: Ionization of argon gas which is filled in the
Geiger tube by x-rays.
 ADVANTAGES: In expensive
Trouble-free
 DISADVANTAGES: only for counting low rates
Efficiency will be less
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29. SOLID- STATE SEMI CONDUCTOR
DETECTOR:
 Electrons produced by x-ray beams are converted
in to conduction bands ,the current which flows
is directly propotional to incident x-rays.
SEMI CONDUCTOR DETECTOR:
 A pure silicon block set up with a thin film
lithium metal placed on to one end.
Semi conductor
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30. X-RAY DIFFRACTION METHODS
1) SINGLE CRYSTAL DIFFRACTOMETER:
A) LAUE METHOD
a)TRANSMISSON METHOD
b)BACK REFLECTION METHOD
B) BRAGG’S SPECTROPHOTOMETER METHOD
2)POWDER CRYSTAL DIFFRACTOMETER
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31. LAUE METHOD
TRANSMISSION METHOD
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32. BACK REFLECTION METHOD
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33. BRAGG’S SPECTROPHOTOMETER
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34. ROTATING CRYSTAL METHOD
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35. POWDER CRYSTAL METHOD
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36. 37

37. APPLICATIONS
1)STRUCTURE OF CRYSTAL:
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38. 2)POLYMER CHARACTERISATION:
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39. 3)PARTICLE SIZE DETERMINATION:
a)Spot counting method:
b)Broadening of diffraction lines
c)Low-angle scattering
4)APPLICATIONS OF DIFFRACTION METHODS TO
COMPLEXES:
a)Determination of cis-trans isomer
b)Determination of linkage isomer
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40. 5)STATE OF ANNEAL IN METALS :
 Well annealed metals are in well ordered crystal form and give
sharp diffraction lines.
 If the metal breaking is present then the x-ray pattern more
diffuse.
6)MISCELLANEOUS APPLICATIONS:
 Soil classification based on crystallinity
 Analysis of industrial dusts
 Weathering and degradation of naturals and synthetic
minerals
 Corrosion products can be studied by this method
 Tooth enamel and dentine have been examined by X-ray
diffraction.
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41. 42

42. PANALITICAL XPERT INSTRUMENT
Features:
 X-ray source: Philips high intensity ceramic sealed tube (3kW)
 Wavelength: Cu Ka (1.5405 Å)
 Incident beam optics: 2 interchangeable fixed slits and one Soller slit.
 Diffracted beam optics: fixed slit plus programmable receiving slit,
graphite analyzer
 Detectors: sealed proportional counter and X'celerator PSD for high
speed data collection
 Sample stage: powder stage, texture cradle with sample translation
 Software: Philips X’PERT suite: Data Collector, Graphics & Identify,
Texture
 XPERT Powder (I) - for high-speed phase identification
 XPERT Thin Film (II) - for thin film, grazing-incidence XRD, texture
measurement
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43. REFERENCES
 Remington 21st edition pg.no.481
 Instrumental methods of chemical analysis by
Gurdeep. R. Chatwal ,12th chapter,pg.no.2.303-2.339
 Analytical chemistry by Clive Whiston
(x-ray methods)
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44. THANK YOU
THANK YOU
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