X-RAY Diffraction Instrumentation: Source, Detector, Application and MCQ
X-RAY DIFFRACTION INSTRUMENTATION :-
- SOURCE X-ray diffraction tube
- High energy e– are produce from heated tungsten filament & this is allowed to impinge on a small metal target (Cu/Mo) in a sealed diffraction tube.
- X-ray generated from metal target is then passed through low absorption beryllium window to focus into the specimen.
- COLLIMATOR :- in order to get a narrow beam of x-ray the x-ray generated by target material is allowed to pass through collimator that consists of 2 sets of closely packed metals plates separated by a small gap. The collimator absorbs all the x-ray except the narrow beam that passes between the gap.
- MONOCHROMATOR
- DETECTOR :-
- Photographic films: time consuming
- Counter methods(better sensitivity wise)
- Geiger muller tube counter :– it is filled with inert gas like argon the counter works on the ‘’principle of gas multiplication’’. Ionization in the gas is caused by the entry of photon or a particulate radiation. The ions are attracted to their appropriate electrode (i.e. to cathode anion to anode) and they gain sufficient energy to eject electrons from the gas atoms as they pass through the gas.Therefore electrons are produced continuously by this process and rapid gas multiplication take place.These create electric pulses which is then amplified electronically and counted by a meter to calculate the number of initial ionization events.
- Proportional counter :– It works on the same principle as the Geiger-muller counter but uses a lower operating voltage.
- Scintillation counter:- produces non continuous light when comes in contact with x-rays e.g. NaI crystal activated by thallium,Anthracene
- Semiconductor:– Lithium drifted germanium or lithium drifted silicon
- GONIMETER:- is a instrument that allows crystal to be rotated to a precise angular position.so as to get good diffraction pattern of the crystal.
APPLICATION :-
- Structure of crystal
- polymer characterization
- particle size determination
- low angle scattering
- determination of cis-trans isomerism
- spot counting method
MCQ
1. Which is Not Application of x ray diffraction ?
A.Determination of cis-trans isomerism in mixture.
B. Study of solid compound crystal structure.
C. Particle size determination.
D. To calculate emf.
2. Which is source production of x ray in x-ray diffraction.
A. Tungsten filament
B. Hydrogen- Deterium lamp
C. Bolometer
D. Mercury arc
3. Which is detector is Not used in x-ray diffraction ?
A. Geiger muller tube
B. Proportional Counter
C. Semi conductor detector
D. PMT
4. Which Part of x -ray instrument is allow crystal to be rotated to a precise angle position ?
A. Geiger muller tube
B. Collimator
C. Tungsten filament
D. Goniometer
5. What is used of x-ray collimator ?
A. Produce x ray
B. Study of shape of crystal
C. To absorbed x -ray
D. None of the above
6. Which is dis advantage of photographic films ?
A. Time consuming method
B. Old method
C. A and B
D. None of the above
7. Which sentence is true about x -ray diffraction ?
A. Assay of drug
B. To determine oxidation number
C. To study of solid compound crystal structure
D. To separate cis – trans mixture
ANSWER KEY
1. D
2. A
3. D
4. D
5. C
6. C
7. C
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REFERENCE :-
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