Nuclear Decay and Radiation

• An example of a radioactive isotope is Carbon 14
• Radioactive decay explained

  • Some isotopes have an unstable nucleus 
  • To become more stable , the nucleus gives out radiation 
  • This is called radioactive decay

  
• Give a definition for radioactive decay

  Radioactive decay is where isotopes that have an unstable nucleus give out radiation to become more stable
• The atom below is giving out radiation from the nucleus so is undergoing radioactive decay

  
• Radioactive decay is a completely random process
• The activity is the rate at which a source of unstable nuclei decay
• The activity of a radioactive source is the rate at which it decays
• Units of measurement for activity

  • Activity is measured in becquerel (Bq)
  • 1 Bq = 1 decay per second
• To measure the activity of a radioactive source , we can use a Geiger-Muller tube

  
• What is count-rate

  The count-rate is the number of decays recorded each second by a detector (e.g. a Geiger-Muller tube)
• Remember that count rate is not the same as activity , due to background activity
• Radioactive nuclei give out radiation
• • One becquerel is equivalent to one count per second 
  • (i.e. 1 Bq = 1 count per second)