Properties of alpha, beta and gamma radiation: Atomic structure: Physics: GCSE (9:1)

• Relative mass and charge of a alpha particle

  Mass = 4 and charge = +2

  
• Relative mass and charge of a beta particle

  Mass = approx. 1/2000 and charge = –1

  
• Relative mass and charge of a gamma ray

  Mass = 0 and charge = 0

  
• Ionising power


  The ability to ionise materials
• Effect of charge on ionising power

  The greater the charge of the radiation, the more it will ionise materials
• Ionising power of an alpha particle

  Highly ionising
• Ionising power of a beta particle

  Moderately ionising
• Ionising power of a gamma ray

  Weakly ionising
• Penetrating power

  The ability to penetrate (pass through) matter

  
• Effect of mass on penetrating power

  The greater the mass of the radiation, the less it will penetrate materials
• Penetrating power of an alpha particle

  Weakly penetrating

  
• Penetrating power of a beta particle


  Moderately penetrating

  
• Penetrating power of a gamma ray

  Strongly penetrating

  
• Materials that stop alpha particles


  Skin or paper

  
• Materials that stop beta particles

  A few millimetres (mm) of aluminium

  
• Materials that stop gamma rays

  Several centimetres (cm) of lead or about 1 metre (m) of concrete

  
• Range (in air)


  How far nuclear radiation can travel in air before it is absorbed
• Range of an alpha particle

  Less than 5 centimetres (cm)
• Range of a beta particle

  About 1 metre (m)
• Range of a gamma ray


  Over 1 kilometre (km)