Alpha Beta and Gamma Decay

• 3 types of radiation

  • Alpha (α)
  • Beta (β)
  • Gamma (γ)
• Penetrating power of alpha, beta and gamma

  • Alpha particles have poor penetrating power - They are absorbed by a single sheet of paper 
  • Beta particles have reasonable penetrating power - They are absorbed by a few millimetres of aluminium 
  • Gamma waves have strong penetrating power - They are absorbed by several centimetres of lead

  
• Range in air of alpha , beta and gamma

  • Alpha particles are large , and can travel 5 cm in air before they collide with air particles and stop 
  • Beta particles can travel 15 cm in air before they collide with air particles and stop 
  • Gamma radiation can travel several metres in air before they collide with air particles and stop

  
• What is ionising power

  • When radiation collides with atoms , that can cause the atoms to lose electrons and form ions 
  • The ionising power is the amount of ions produced by knocking electrons from atoms when atoms collide with radiation

  
• Ionising power of alpha , beta and gamma

  • Alpha particles have strong ionising power - they produce a large amount of ions when they collide with a material and cause its atoms to lose electrons 
  • Beta particles have reasonable ionising power - they produce a reasonable amount of ions when they collide with a material and cause its atoms to lose electrons
  • Gamma particles have poor ionising power - they produce a small amount of ions when they collide with a material and cause its atoms to lose electrons

  
• Components of alpha radiation

  • Has 2 neutrons and 2 protons 
  • Is the same as a helium nucleus 
  • Is ejected from the nucleus
• Hazards of alpha radiation

  Highly likely to be absorbed (due to its poor penetrating power) and cause damage if passing through living cells
• Components of beta radiation

  • An electron 
  • Ejected from the nucleus at very high speed
  • Formed inside the nucleus  
  • Ejected from the nucleus when a neutron turns into a proton and electron
• Hazards of beta radiation

  • Likely to cause damage if absorbed by living cells 
  • Can penetrate the body to the inner organs