a. The stationary anode X-ray tube b. The rotating anode X-ray tube c. The X-ray tube housing d. The X-ray tube focal spot e. Anode angle f. Maximum anode heat input g. The X-ray tube filament h. Filament focus

1. THE X-RAY TUBE
BY ABRAM MALAK BOSHRA
SUPERVISED BY: DR ASHRAF MAHROOS
MINIA UNIVERSITY
FACULTY OF ENGINEERING
BIOMEDICAL ENGINEERING DEPARTMENT

2. Contents
• e. Anode angle
• f. Maximum anode heat input
• g. The X-ray tube filament
• h. Filament focus
• a. The stationary anode X-ray
tube
• b. The rotating anode X-ray tube
• c. The X-ray tube housing
• d. The X-ray tube focal spot

3. a. The stationary anode X-ray tube
• Found in portable X-ray & dental units.
• Anode is a small insert of tungsten inside a large copper
support.
• The copper is to help adsorb the heat produced.
• Focal spots are larger than for the rotating anode type
,as the heat produced is in a very small area.

4. b. The rotating anode X-ray tube
• Heat produced is spread around a
wide area.
• Much smaller focal spots may be
used, together with an increase in
output.
• Rotation is achieved by attaching a
copper cylinder to the anode. This
forms the 'rotor' of an induction
motor.

5. c. The X-ray tube housing
• The housing is lead lined
• Radiation only exits via the port in
front of the focal spot.

6. d. The X-ray tube focal spot
• Focusing a beam of electrons, onto
the anode results in an effective
small area of X-rays known as the
'focal spot'

7. e. Anode angle
• The wider the anode angle, the greater will be the
film coverage at a specific distance.
• However, to maintain the same focal spot size, the
length ‘L' of the electron beam must be reduced.
• This results in a smaller area to dissipate the
immediate heat, so the maximum output of the
tube has to be reduced

8. f. Maximum anode heat input
The maximum heat input for the X-ray tube anode is determined by:
• The anode material.
• Anode rotation speed.
• Anode diameter.
• Focal spot size.
• The kV waveform. (Single-phase, or three-phase)

9. g. The X-ray tube filament
• To emit electrons, the filament must be brought
to white heat temperature (1315+ °C).
• As the temperature increases, a point is reached
where, despite further increases in temperature,
only a small increase in emission results.
• In this area tungsten evaporation also increases,
greatly reducing the filament life.
• When the kV is increased, electron emission
from the filament to the anode also increases.

10. h. Filament focus
• To enable a tight beam of electrons to
the anode, the filament is placed inside
a 'focus cup'.
• The focus cup is connected directly to
the common center point of the
cathode.
• the two filaments are placed side by
side, and angled, so to strike the same
anode position.

11. Thank You