Xray Tube Design and function

• Fill up

  A) Molybdenum Anode

  B) Pyrex or Borosilicate Glass Envelope

  C) High tension cable broad focus fine focus

  D) Nickel focusing cup

  E) Tungsten filament

  F) Anode rotor

  
• fill up

  A) Expansion bellows

  B) Cathode high tension insulator

  C) Pyrex or Borosilicate Glass Envelope

  D) stator induction magnets

  E) anode high tension insulator

  F) oil

  G) stator current supply

  H) lead tube shielding

  I) beryllium window

  J) lead cup

  K) cath

  L) rotor

  
• fill up

  A) stator induction magnets

  B) cathode assembly

  C) lead tube housing

  D) high tension cable broad focus fine focus

  E) collimator box

  F) mirror

  G) collimator blades

  H) collimator light bulb

  I) beryllium window

  J) tungsten / rhenium anode target

  K) anode rotor

  
• Cathode is positively charged or negatively charged?

  negative
• Anode is positively charged or negatively charged?

  Positive
• Material used for Tube housing

  Lead
• Material used for insert envelope

  Glass / pyrex or evacuated metal
• Material used for Cathode support

  ceramic
• Material used for Cathode

  Tungsten wire
• Material used for Focusing cup

  molybdenum, steel or nickel
• Material used for rotor

  Copper or soft iron
• Material used for stator

  Electromagnet
• Material used for Anode disk

  Tungsten
• Material used for Anode stem

  Molybdenum
• 1. Electrons are slowed down or stopped within the anode target.
  2. Excitation occurs in the tungsten particles.
  3. Heat is dissipated.
  4. Electrons leave the tungsten atom.
  5. Potential difference is applied.
  6. Electrons are accelerated toward the anode.
  7. A space charge is formed around the cathode.
  8. X-ray beam exits the tube.
  9. Tungsten filament is heated (2000°C, thermionic emission).

  9 2 4 7 5 6 1 3 8
• Why is Lead used for tube housing?

  Excellent X-ray absorber for radiation shielding.
• Why is glass / pyrex used for insert enevelope

  Vacuum-tight and heat-resistant to withstand high temperatures.
• Why is ceramic used for cathode support

  Electrically insulates and tolerates heat.
• Why is tungsten wire used for cathode (filament)

  Very high melting point and low work function for efficient thermionic emission.
• Why is molybdenum, steel or nickel used for focusing cup

  Electrically conductive, heat-resistant, and shapes the electron beam.
• Why is copper or soft iron used in rotor

  Good thermal conductivity (copper) or magnetic properties (soft iron) for efficient rotation.
• why is electromagnets used in stator

  Creates the rotating magnetic field to spin the anode.
• Why is tungsten used in anode disk

  High atomic number for efficient X-ray production and excellent heat tolerance.
• Why is molybdenum used in anode stem

  Low thermal conductivity to protect the rotor while withstanding heat.