Revision Notes

5.2.1 Detection of Radioactivity

Background Radiation: Basics

  • Background radiation is the radiation that is always present around us in the environment

background-radiation, IGCSE & GCSE Physics revision notes

Background radiation is the radiation that is present all around in the environment

  • Although most background radiation is natural, a small amount of it comes from artificial sources, such as medical procedures (including X-rays)
    (Radiation from Nuclear Power come to less than 0.1% of the total)
  • Levels of background radiation can vary significantly from place to place


Detecting Radiation

  • When radiation passes close to an atom, it knocks out electrons, ionising the atom
  • Radiation detectors work by detecting the presence of these ions or the chemical changes that they produce
  • Examples of radiation detectors include:
    • Photographic film (often used in badges)
    • Geiger-Muller (GM) tubes
    • Ionisation chambers
    • Scintillation counters
    • Spark counters


Geiger-Counter, IGCSE & GCSE Physics revision notes

A Geiger-Muller tube (or Geiger counter) is a common type of radiation detector


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