Radiation

• Decay


  The process by which a radioactive nucleus spontaneously transforms into a more stable configuration
• Carbon-12 is stable, Carbon-14 is radioactive
• Difference between the number of protons and neutrons in the nucleus

  Causes Carbon-14 to be radioactive and decay
• Radioactive decay causes Carbon-14 to become more stable by emitting radiation
• Radioactive decay is a random process, so it is impossible to predict when a specific nucleus will decay
• Radioactive decay can be described statistically, like throwing dice
• Due to the random nature of radioactive decay, measurements and calculations should account for uncertainty
• Isotopes


  Atoms of the same element that have the same number of protons but a different number of neutrons
• Types of radiation


  • Alpha
  • Beta
  • Gamma
• Alpha radiation


  • High energy, cannot penetrate paper
  • Absorbed by the skin
• Gamma radiation


  • High energy, highly penetrating
  • Reduced by thick, dense shielding
• Radiation equations must balance before and after a radioactive decay
• The mass number and atomic number must be the same before and after a radioactive decay
• Background radiation is present everywhere due to natural and man-made sources
• The level of background radiation varies depending on location due to differences in rocks, buildings, and cosmic ray exposure
• Decay


  The process by which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves
• Carbon-12


  • Stable isotope of carbon
• Carbon-14


  • Unstable isotope of carbon due to imbalance between number of protons and neutrons in the nucleus
• Radioactive decay


  1. Nucleus tries to become more stable by releasing radiation

  2. Random process, cannot predict when a nucleus will decay

  3. Probability can be used to estimate decay
• Background radiation is present from both natural and man-made sources
• Natural sources of background radiation

  • Radon gas
  • Rocks and buildings
• Man-made sources of background radiation

  • Medicine (x-rays)
  • Nuclear power testing
  • Food
  • Cosmic rays
• Background radiation levels vary due to differences in local geology, buildings, and altitude
• Equations for nuclear decay


  • Total nucleon number must be the same before and after
  • Total proton number must be the same before and after
• Radium-226 decay


  • Radium-226 releases an alpha particle to become radon-222
• Isotopes


  Atoms with the same number of protons but different numbers of neutrons
• Types of radiation


  • Alpha
  • Beta
  • Gamma
• Radiation types


  • Alpha: low penetrating power, absorbed by paper
  • Beta: medium penetrating power, absorbed by aluminium
  • Gamma: high penetrating power, reduced by thick lead
• Radiation can be investigated by using absorbers and a detector to determine the type of radiation emitted