This presentation is about conventional X-Ray Tubes. It is very clear and concise. Easy to understand for everyone. It includes history, types, construction, working , advantages and disadvantages also in very simple and in effective manner.

1. CONVENTIONAL X-RAY TUBE AND IT'S
CONSTRUCTION
PRESENTED BY- VIBHA JOSHI
MASTERS IN RADIO
IMAGING TECHNOLOGY- 1ST SEM

2. CONVENTIONAL X-RAY TUBES
• The x-ray tube which behave in
traditional way is known as
conventional x-ray tubes
• Sir Wilhelm Conard Roentgen
was a German mchanical engineer
and physicist who on 8th
November, 1895 produced and
detected X-Rays

3. BASIC PRINCIPLE
 The basic principle of x-ray
production is as followed:
• High voltage across anode and
cathode
• Electrons emitted
• Accelerated toward anode
• Production of x-rays takes place

4. TYPES OF CONVENTIONAL X-RAY TUBE
CROOK'S TUBE
COOLIDGE TUBE

5. CROOK'S TUBE
• It is an experimental discharge tube
with partially vacummated which is
generally used for experiments.
• It was discovered by a physicist Sir
William Crookes around 1865-
1875.
• Cathode rays streams of electrons
were discoverd in this tube.
• The crook's tube consist of
1. Glass bulb of various shapes
2. two metal electrodes i.e. anode
and cathode
• When high voltage applied between
them, electrons are projected in
straight lines from the cathode.

6. continue.....
• It is also known as cold tubes/ discharge
tube/ cathode ray tube/ gas tube.
• It is used till 1920
• It's action depend upon the presence of
small residual amount of gas present in it.
CROOK'S TUBE CONSIST OF :
• Tube Envelope
• Anode
• Cathode
• Anti- Cathode
• Softener

7. TUBE ENVELOPE :
• It covers the tube.
• Partially evacuated(to remove air from so as to make
a vacuum) glass bulb .
• Inert gases are used due to slow down evaporation
rate of the filament.
• Na/Cerium used as a core
• Air Pressure of 10-6 to 5x10-8
ANODE :
• Platinum is used
• (At No.- 78 , MP- 1768'C )
Ques: Why platinum used as anode?
Ans: Good resistance of corrosion
Due to unreactive nature appartus use for scientific
labs, surgical tools as well as dental fillings too.

8. CATHODE :
• Aluminium is used
• (At No.- 13 MP- 660'C)
Ques : Why we use Aluminium?
Ans :s Highly thermal conductivity

9. ANTICATHODE :
• Most of thE early x-ray tubes known as bi-anoDe tubes i.e. had two
anodes; the proper anode and auxiliary anode known as anticathode.
• It is made up of Copper plate and electrically connected to the anode so
that both possessed a positive charge.
• This is the act as target electrode for stream of electron.
SOFTENER :
• It is used to regulate gas pressure which is 10-6 to 5x10-8 P

10. PRODUCTION OF X-RAYS IN CROOK'S TUBE
• A high voltge current is induce
between electrodes and this made
ionization.
• Thus the electron flow from cathode
to target anode.
• When these electrons hit the target
, production of bremsstrahlung
radiation takes place.
DISADVANTAGES : Unreliable
Overheating

11. COOLIDGE TUBE
• Coolidge tube is advancement of
Crook's Tube.
• It is improved by Sir William
Coolidge in 1913.
• The another name of the tube is
Hot cathode tube.
• The characteristic features of
coolidge tube are as follow:
i. highly vacuum
ii. heated filament
iii. thermionic element

12. CONSTRUCTION
• Tube envelope
• Anode assembly
• Cathode assembly
TUBE ENVELOPE :
• Spherical glass tube consist of two electrode arms i.e.
anode and cathode arm
• Made up of Pyrex glass
• Internal pressure 10-8 mmHg

13. ANODE ASSEMBLY :
• Anode assembly refers to as target where electrons get strikes.
• Stationary anode was in used.
• Tungsten material is used .
Ques: Why Tungsten is used ?
Ans : Because of higher melting point upto 3422'C
It is a good conductor of heat
Doesn't evaporate easily (5600'C)
CATHODE ASSEMBLY :
• It consist of focusing cup and filament.
Focusing Cup- It is made up of Mo and anticorrosive in nature.
It's main fuction is to streamline the electrons.

14. FILAMENT :
• It is negatively charged
• Made up of W due to high melting
a n d e v a p o r a t i n g p o i n t s .
• Emission of electron done by
filament.

15. ADVANTAGES :
• Stability
• Intensity and energy can be
controlled
Furthur advancement takes place on
the basis of anode. Previously
stationary anode was in used but in
improved modality ROTATING
ANODE X-RAY TUBE is used.

16. • CONSTRUCTION-
i. Glass Envelope
ii. Anode assembly
iii. Cathode assembly

17. GLASS ENVELOP :
• Made up of Borosilicate glass (Pyrex glass)
• It is cylinderical in shape and hold the electrodes
• It's size is approx 30cm-50cm in length and 20cm
broad
• Highly evacuated

18. ANODE ASSEMBLY :
• Anode assembly is refers to target where electrons pit on the spot.
• 90% of W and 10% of rhenium is used due to high thermal capacity.
• Anode angle : 7-17'
• Rotation per minute : 3000-9000 rotation
ANODE FOCAL SPOT :
• Portion of anode which is useful to capture the electron stream
• There are 2 focal spot and only one is used at a time
• Small focal spot and Large focal spot
ANODE DISK :
• Mo material is used.
ANODE ROTOR :
• Cu and Fe is used due to thermal conductivity

19. CATHODE ASSEMBLY :
• It is the sppot from where electrons emit.
Cathode assembly consist of focuing cup and
filament.
FILAMENT :
• It is made up of W wire in the form of coil.
• 1-3% of THORIUM added for better emission of
electrons, prevent breakage and evaporation
• There are 2 filaments - Small filaments : 2mm-
7mm in size
Large filaments : 7mm-
15mm in size
FOCUSING CUP :
• It is negatively charged and focuses the
electron towards target.
• It overcome the tendency of electrons to spread
due to repulsion

20. ADVANTAGES :
• Provide greater area for
bombardment
• Better heat dissipation than
stationary anode tube
• Shelf life increase
• Pitting of electrons is vary
TUBE FAILURE :
• Anode pitting
• Rapid heat increase at anode
• Filament vaporization

21. CARE OF X-RAY TUBE :
• Warm up the anode
• Use lower tube current
• Don't make high exposure on cold target
• Don't rotate the tube housing rapidly. It may lead to cracking of housing

22. THANK YOU