X-Ray Tube

• What is the primary piece of equipment used by radiographers?

  X-Ray Tube
• How are X-Rays produced in the X-Ray tube?

  By targeting accelerated electrons onto a surface
• What percentage of energy produced in the X-Ray tube is X-Rays?

  1%
• What is contained within the cylindrical tube of the X-Ray tube?

  The X-Ray tube itself
• What are the essential features of an X-Ray tube?

  • Cathode: Heated metal filament for electrons
  • Evacuated Chamber: Allows potential difference
  • Anode: Metal target for converting energy to X-Rays
  • Thin Window: Transparent to most X-Rays
• What are the two main components of an X-Ray tube structure?

  1. Insert: Anode and cathode in an evacuated envelope
  2. Shield: External casing for protection
• What is the role of the cathode in the X-Ray tube?


  To provide electrons
• What is thermionic emission in the context of the cathode?

  Production of electrons from heated filaments
• What materials are the filaments in the cathode typically made of?

  Tungsten
• What is the difference between fine focus and broad focus filaments?

  Fine focus minimizes geometric unsharpness
• How does broad focus affect heat dissipation in the anode?

  It improves heat dissipation due to larger area
• What phenomenon is introduced by using a larger area of the anode?

  Penumbral shadowing
• What is the role of the focusing cup in the X-Ray tube?

  To focus electrons onto the anode
• What materials are typically used for the focusing cup?


  Nickel or stainless steel
• What is the anode in the X-Ray tube?

  An electrode of positive potential
• What are the two types of anodes in X-Ray tubes?

  1. Stationary: Copper and tungsten construction
  2. Rotating: Disc with a target track
• What is the construction of a stationary anode?

  Copper with a tungsten target plate
• Why is copper used in the stationary anode?

  For its good thermal conductivity
• What is the target track in a rotating anode made of?

  Mainly tungsten, alloyed with rhenium
• What is tube loading in the context of X-Ray tubes?

  The amount of heat produced at the anode
• What factors determine tube loading?

  kV and mA selection prior to exposure
• What is tube rating in X-Ray tubes?

  • Safe combinations of kV, mA, and time
  • Prevents thermal damage to the tube
• What are X-Ray tube envelopes made of?

  Glass (Pyrex) or metal-ceramic
• What is the purpose of the evacuated envelope in X-Ray tubes?

  To allow uninterrupted electron flow