History of X-ray and History of xrd and Basic Prinicpal of Xrd and Instrumentation of XRd and application of XRD

1. X- Ray Diffraction
Presented
By
Waqar Ahmad Khan
M.Phil Chemistry
Sarhad University Of Science And Technology,Hayatabad,Peshawar,Pakistan

2. CONTENTS
HISTORY OF X-RAY AND XRD
INTRODUCTION OF XRD
PRINICIPAL OF XRD
BRAGG’S EQUATION
INSTRUMENTATION OF XRD
APPLICATION OF XRD

3. HISTORY OF XRAY AND XRD
1868: X-rays Discovered by German Scientist Röntgen.
Wilhelm Roentgen, a German professor of physics, was the first person to
discover electromagnetic radiation in a wavelength range commonly known as X-
rays today.
he was honored with the first he first Nobel Prize in Physics in 1901.
von Laue (9 October 1879 – 24 April 1960) was a German physicist who won
the Nobel Prize in Physics in 1914 for his discovery of the diffraction of X-
rays by crystals.
1912: Bragg’s Discovery XRD Bragg’s was British scientist.
VON LAUE
RONTGEN
BRAGG’S

4. INTRODUCTION OF X-RAYS
 i) Hard x-rays: which have high frequency and have more energy.
ii) soft x-rays: which have less penetrating and have low energy.
X-RAYS:
1.X-rays are short wave length electromagnetic radiations produced by the
slowing of high energy electrons or by electronic transitions of electrons in the
inner orbital of atoms .
2.X-ray region 0.1to100 A˚ .
3.Analytical purpose 0.7 to 2 A˚.

5. X-RAYS DIAGRAME

6. INTRODUCTION OF XRD
The atomic planes of a crystal cause an incident beam of Xrays to interfere
with one another as they leave the crystal.
The phenomenon is called X-ray diffraction

7. PRINCIPAL
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.

8. BRAGG’s EQUATION
The path difference between ray 1 and ray 2 = 2d SinQ For constructive
interference:n=
Constructive interference of the reflected beams emerging from two different
planes will take place if the path lengths of two rays is equal to whole
number of wavelengths”.
for constructive interference this is called as BRAGG’S
LAW. 

sin2
n
d 

 2
1
sin d

9. BRAGGS EQUATION DIAGRAME

10. BRAGG’S EQUATION CONTINUE

11. BRAGG BRENTANO DIFFRACTOMETER
ONLY ONE FAMILY PEAKS

12. INTRUMENTATIONS OF XRD

13. INSTRUMENTATION OF XRD

14. PRODUCTION OF X-RAYS
X-rays are generated when high velocity electrons affect on a metal target.
Approximately 1% of the total energy of the electron beam is converted into
x-radiation.
The remainder being degenerate as heat.

15. PRODUCTION OF X-RAYS
Many types of x-ray tubes are available which are used for producing x-
rays.
 a .Positive voltage in the form of anode having a target a .
 b . Battery to emit thermoionicelectrons .
 C. Cathode –filament of tungsten metal .
 The electrons are accelerated towards the target a .
 On striking the target the electrons transfer their energy to its metallic
surface which gives off x-ray radiation.

16. PRODUCTION OF X-RAYS
A.ANODE
BATTERY
CATHODE

17. COLLIMATOR
In order to get a narrow beam of x-rays, the x-rays generated by the
target material are allowed to pass through a collimator which consists of two
sets of closely packed metal plates separated by a small gap.
 The collimator absorbs all the x-rays except the narrow ray that passes
between the gap.

18. DETECTORS
SCINTILLATION DETECTOR:
In a scintillation detector there is large sodium iodide crystal activated with a
small amount of thallium .
When x-ray is incident upon crystal , the pulses of visible light are emitted
which can be detected by a photo multiplier tube.
Useful for measuring x-ray of short wavelength.
 Crystals used in scintillation detectors include sodium iodide , anthracene
,napthalene and p-terphenol.

19. COUNTER METHOD
a) Geiger - Muller tube counter
Geiger tube is filled with inert gas like argon.
Central wire anode is maintained at a positive potential of 800 to 2500V.
 The electron is accelerated by the potential gradient and causes the
ionisation of large number of argon atoms ,resulting in the production of fall
of electrons that are travelling towards central anode.

20. COUNTER METHOD CONTINUED

21. APPLICATION OF XRD
STRUCTURE OF CRYSTALS:
a-x-ray design of salt Nacl .
b-x-ray pattern of salt Kcl
c-x-ray pattern of mixture of Nacl &Kcl
d-x-ray pattern of a powder mixed crystal of Nacl & Kcl

22. Application of XRD Continue

23. STRUCTURE OF CRYSTAL

24. POLYMER CHARACTERISATION
Determine degree of crystanillity.
Non-crystalline portion scatters x-ray beam to give a continuous
background(amorphous materials).
Crystalline portion causes diffraction lines that are not continuous.(crystalline
materials).
To determine the atomic structure of the atoms.

25. State of anneal in metals
XRD is used to to test the metals without removing the part from its position
and without weakening it.
PARTICLE SIZE DETERMINATION
Spot counting method: v=V.δθ.cosθ/2n
V=volume of individual crystallite
V=total volume irradiated
n=no. of spots in diffraction ring
δθ =divergence of x-ray beam

26. BRUKER X-RAYS DIFFRACTION D8
DISCOVERY INSTRUMENT

27. REFERENCES
1)Instrumental methods of chemical analysis ,B.K.sharma,17th edition
1997-1998,GOEL publishing house.page no:329-359
2)Principles of instrumental analysis,5th edition ,by Dougles
a.skoog,f.James holles,TimothyA.Niemen.page no:277-298
3)Instrumental methods of chemical analysis ,Gurudeep
R.chatwal,sham k.anand,Himalaya publications page no:2.3032.332
4) http://www.scienceiscool.org/solids/intro.html
5) http://en.wikipedia.org/wiki/X-ray_crystallography
www.wikpedia x-rays and xrd history .

28. END