Wilhelm Roentgen discovered X-rays in 1895 and called them X-rays because their nature was unknown at the time. Max von Laue discovered X-ray diffraction in crystals in 1914, for which he won the Nobel Prize. X-rays are produced when high-speed electrons collide with a metal target. When X-rays pass through a small opening and scatter in different directions, it is called X-ray diffraction. This technique is used to study the crystal structure of solids. Bragg's law describes the diffraction of X-rays by crystals and can be used to determine crystal structures. X-ray diffraction is used in fields like soil classification, industrial material analysis, corrosion examination, and determining the structures of proteins

1. Submitted By:
Muhammad Saqib Sheraz
BS-Biotechnology 5th - Term
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2. INTRODUCTION:
 X-rays were discovered by Wilhelm Roentgen
who called them x-rays because the
nature at first was unknown so, x-rays
are also called Roentgen rays.
 X-ray diffraction in crystals was discovered by Max
von Laue for this he has awarded Nobel Prize in 1914.
Max Von
Laue
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3. X-Ray and its Production
 An electromagnetic waves of high energy and very
short wavelength (10-7 to about 10-15 nm), which is
able to pass through many materials is known as
X-RAYS.
PRODUCTION:
 X-rays are produced whenever high-speed
electrons collide with a metal target.
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4. Production of X-ray
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5. X-ray Diffraction (XRD)
 When X-ray waves are passed through a very small
opening and is scattered in different directions it is
called as X-ray diffraction.
 This technique is mainly used to study the structure of
crystalline solids.
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6. PRINCIPLE
X-ray
diffraction is based on constructive interference of
monochromatic x-rays and a crystalline sample. These x-rays
are generated by a cathode ray tube, filtered to produce
monochromatic radiation ,collimated to concentrate and
directed towards the sample. The interaction of incident
rays with the sample produces constructive interference
when conditions satisfy Bragg’s Law.
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7. Bragg’s Law.
An English physicists Sir W.H.Bragg and his son Sir
W.L.Bragg developed the below relationship.
The Bragg’s were awarded the Nobel Prize in Physics in
1915 for their work in determining crystal structures
beginning with NaCl, ZnS and Diamond.
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8. Instrumentation of XRD
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9. XRD In Protein Study
 In order to study the structure of any unknown protein
through X-ray Diffraction we do following steps;
i. First of all the extracted protein is crystallized.
ii. Then the X-rays are focused upon protein crystal.
iii. Most of rays pass out straight without being deflected,
only few rays are scattered at different angles which
reinforces with each other to create an X-ray pattern
upon photographic plate.
iv. From the dotted pattern we can tell the structure of that
protein.
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11. Figure: X-ray diffraction image of a crystal of lysozyme
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XRD IN DNA STUDY

13. APPLICATIONS
 Soil classification based on crystallinity
 Analysis of industrial dusts
 Assessment of weathering & degradation of
minerals & polymers
 Study of corrosion products
 Examination of tooth enamel & dentine
 Examination of bone state & tissue state
 Structure of DNA&RNA
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14. A Modern X-ray Diffractometer
X-ray Tube
Detector
Sample stage
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