X-Ray Tube Flashcards
What are the primary components necessary for X-ray production?
*Source of electrons
*appropriate target material
*high voltage
*vacuum
What is the function of the cathode assembly in an X-ray tube?
Produce thermionic cloud, conduct high voltage, focus electron stream
The cathode assembly is the negative side of the X-ray tube.
What materials can the filament in the cathode assembly be made of?
- Thoriated tungsten
- Rhenium
- Molybdenum
Thoriated tungsten is most commonly used due to its high melting point and resistance to vaporization.
What is the purpose of the focusing cup in the cathode assembly?
Narrows the thermionic cloud
The focusing cup is made of nickel and helps direct electrons toward the anode.
What is the space charge effect?
Negative charges from emitted electrons oppose additional electron emission
This effect limits the mA ranges of the X-ray tube.
True or False: The anode assembly is the positive side of the X-ray tube.
True
The anode serves as the target surface for electrons and conducts high voltage.
What are the two types of anodes?
- Stationary
- Rotating
Rotating anodes provide better heat dissipation during operation.
What is the primary thermal conductor in the anode assembly?
Anode (target)
The anode conducts heat away from the focal track.
Why is tungsten the material of choice in the anode target?
- High atomic number
- High melting point
- Heat-conducting ability
What is pitting in the context of an X-ray tube?
Vaporization of target track material due to normal use
Pitting reduces the efficiency of the tube.
What is the effective focal spot?
Area of the focal spot projected out of the tube
It is influenced by the actual focal spot, filament size, and anode target angle.
Fill in the blank: The __________ effect results in greater radiation intensity on the cathode side of the X-ray tube.
anode heel
This phenomenon is due to the geometry of the angled anode target.
What does the stator do in an X-ray tube?
Turns the anode
The stator is the only part located outside the vacuum of the envelope.
What is the role of the dielectric oil in an X-ray tube?
Insulates high-voltage components, absorbs heat
The oil helps maintain the temperature and prevents electrical hazards.
What can cause ghosting of structures in X-ray imaging?
Off-focus or extrafocal radiation
This occurs when high-voltage electrons produce scattered photons.
