Types of radiation

• Nucleon number


  Number of protons + number of neutrons
• Proton number


  Number of protons
• The number of protons in a nucleus determines which element it is
• Isotopes


  Nuclei with the same proton number but different nucleon number, so different number of neutrons
• Sources of background radiation

  • Radon (a gas formed in rocks below the ground)
  • Rocks and buildings
  • Food
  • Cosmic rays
  • Medicine e.g. X-rays
  • Nuclear power and testing (around 1%)
• The level of background radiation varies from one place to another due to the different rocks in each area, the types of buildings and height above sea level
• Investigating a radioactive source

  1. Place absorber

  2. Take reading

  3. Determine type of radiation
• In the example, there would be 330 cpm of alpha, no beta, and 20 cpm of gamma
• Nuclear decay equations


  1. Total nucleon number must be the same before and after

  2. Total proton number must be the same before and after
• Radium-226 decays to radon-222 by releasing an alpha particle
• Radioactive decay


  Random process where unstable nuclei try to become more stable by releasing radiation
• Types of radiation


  • Alpha
  • Beta
  • Gamma
• Alpha radiation


  • Helium nucleus
  • Low penetrating power
  • Low danger outside body, high danger inside body
• Beta radiation


  • High energy electron
  • Medium penetrating power
  • Medium danger outside and inside body
• Gamma radiation


  • Electromagnetic wave
  • High penetrating power
  • High danger outside and inside body