Using radiation

• Entry Level Certificate
• Learning objectives


  Know how radiation can be used<|>Know how the radiation is suited to the task
• Uses of alpha radiation


  • Smoke alarms
• How smoke alarms work

  1. Alpha radiation helps make an electric circuit

  2. Smoke absorbs the radiation

  3. Electric circuit breaks

  4. Alarm is triggered
• Alpha radiation


  • Most ionising
  • Easiest to stop
  • Strongly ionising
  • Absorbed by smoke
  • Cannot pass through plastic case
• A low dose of gamma radiation will do the least damage to living cells
• Gamma radiation


  • Hardest to stop
  • Least ionising type
  • Used in medicine
  • Can pass through the body
  • Weakly ionising
• Use of beta radiation

  1. Beta source placed above foil

  2. Geiger tube placed below

  3. Amount of beta radiation changes with foil thickness

  4. If foil is too thick, Geiger reading decreases

  5. If foil is too thin, Geiger reading increases
• No alpha radiation would pass through the foil at all
• Gamma would pass straight through the foil even if it was very thick
• Gamma radiation as a medical tracer


  Injected into a patient<|>Detected by a gamma camera<|>Allows doctors to see how the body is working
• Uses of gamma radiation

  • Medical tracer
  • Kill cancer cells
• A larger dose of gamma radiation can be used to kill cancer cells
• When there is a problem in an underground pipe, a radioactive source is put into one end of the pipe
• The movement of the radioactive source is then tracked above the ground