nuclear radiation

• What is radioactive decay?

  Emission of nuclear radiation by unstable nuclei
• What happens during radioactive decay?

  Nuclei become more stable through radiation emission
• What is ionisation in the context of radioactive decay?

  Knocking electrons out of atoms
• What are the types of radiation and their characteristics?

  • Alpha:
  • Nucleus loses two protons and two neutrons
  • Highest ionising power
  • Travels a few centimetres in air
  • Stopped by a sheet of paper
  • Beta:
  • A neutron changes into a proton and an electron
  • High ionising power
  • Travels 1m in air
  • Stopped by a few mm of aluminium
  • Gamma:
  • Energy is transferred away from the nucleus
  • Low ionising power
  • Virtually unlimited range in air
  • Stopped by several centimetres of thick lead or meters of concrete
• What is the unit of activity for a radioactive source?

  Bequerel (Bq)
• What does 1 Bq represent?

  One decay per second
• How is count rate recorded?

  Using Geiger-Muller tubes
• How do you calculate count rate after n half-lives?

  Initial count rate / $2^n$
• What is the definition of half-life?

  Time for half of unstable nuclei to decay
• What does the net decline in activity represent?

  Reduction in activity / original activity
• How can ionising radiation affect living cells?

  It can damage or kill them
• Why is alpha radiation dangerous inside the body?

  It affects all surrounding tissue
• How does beta and gamma radiation affect the body?

  They can penetrate into tissues inside and outside
• What is irradiation?

  Exposure of an object to nuclear radiation
• How can irradiation be prevented?

  By shielding, removing, or moving away
• What is contamination in the context of radiation?

  Atoms of radioactive material on or in an object
• What happens to an object that is contaminated?

  It remains exposed to radiation
• What are the methods to protect against irradiation and contamination?

  • Maintain distance from the radiation source
  • Limit time near the source
  • Shield from radiation
  • Peer review studies on radiation effects