X-Ray Beam

• In order to have x-ray production what is required ?

  a rapidly moving stream of electrons to decelerate or stop
• coiled tungsten wire; source of electrons during x-ray production

  filament
• nickel ; surrounds the filament and allows electrons to flow freely across the tube from cathode to anode; keeps cloud of electrons emitted from the filament from spreading apart . Focuses stream of electrons

  focusing cup
• negative = cathode
• positive = anode
• What type of energy of electrons is produced during x-rays and heat ?

  kinetic energy
• What are the to filaments in a dual focus tube ?

  Large

  Small
• What makes up a cathode ?

  filament and focusing cup
• What is the source of electrons on a cathode ?

  filament
• What makes up an anode ?

  molybdenum

  copper

  tungsten

  graphite
• What do the materials in a anode allow ?

  thermal and electric conductive properties
• Anode target metal causes electrons to abruptly decelerate and stop
• Tube current is the flow of electrons from cathode to anode
• What are the components of a rotating anode tube ?

  stator and rotor
• How much is the face of the anode angled to help x-ray exit the tube ?

  5 to 20 degrees
• electric motor that turns the rotor at a very high speed

  stator
• made of copper; connected to anode target through anode stem causing target to rapidly rotate during x-ray production

  rotor
• How much of heat is produced in a x-ray tube ?

  99 %
• What is the only thing outside of the x-ray tube ?

  stator
• Off-focus is reduced in metal envelopes
• What are the two additional function of the envelope ?

  Provides insulation from electrical shock

  Dissipates heat in x-ray tube
• All components surrounded by metal tube housing on all sides except for a port/window
• Tube housing lined with lead to stop leakage radiation
• How fast does the electrons flow outside of the tube ?

  travels at half the speed of light
• German for breaking or slowing down

  Bremsstrahlung
• What does strong electrostatic force of positively charge nucleus causes negatively charged electron to ?

  Slow down , then

  Lose energy , then

  Suddenly change direction
• stronger attractions mean more energy will be lost from projectile electron
• energy lost reappears as x-ray photons
• more energy lost = higher energy x-ray photons
• Projectile electrons traveling further from nucleus create x-ray photons with less energy
• Brems interactions occur when projectile ( incident ) electron avoids orbital electrons of tungsten atom and travels closely to atom's nucleus
• When below 70 kvp - 100 % of x-ray beam results from berms interaction
• When above 70 kvp - 85 % of x-ray beam results from Brems interaction
• nucleus = positive
• 1 % of the electron kinetic energy is converted at x-ray
• What part of the x-ray tube has a high negative charge strongly repels electrons?

  cathood side
• What part of the x-ray tube is considered to have an electon stream away from cathode (-) toward anode (+) ?

  cathode side
• Diagnostic energy range range is 30 to 150 kev
• What x-ray has a technic below 70 kvp which will result in a brems reaction ?

  Hand x-ray
• What part of the x-ray tube has a high positive charge strongly attracts electrons in the tube current ?

  anode side