Ionising Radiation & Detectors (OCR A Level Physics)

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Ionising Radiation & Detectors

  • Ionising radiation include alpha, beta and high-energy electromagnetic radiation such as X-rays, gamma rays and UV
  • They are used in smoke detectors and in many medical applications, such as:
    • Disinfecting medical instruments
    • X-rays
    • Radiotherapy
    • CT scans

  • These normally use X-rays, gamma rays or radioactive tracers
  • In those areas of industry and medicine, where people are routinely working with ionising radiations, various safety procedures are put in place
  • Workers are routinely monitored to check the levels of radiation that they are exposed to and strict limits are placed on what they can receive

radiation-badge, IGCSE & GCSE Physics revision notes

A badge containing photographic film can be used to monitor a person’s exposure to radiation

  • Limits are often placed on the amount of time that workers can spend using radioactive materials.
  • Where feasible, barriers will be placed between the worker and the source in order to absorb the radiation
    • Doctors, for example, will leave the room whilst carrying out certain procedures (including x-rays) in order to minimise exposure.

  • Areas or containers that pose a radiation hazard should have the appropriate radiation hazard symbol

Radiation-Hazard, IGCSE & GCSE Physics revision notes

Radiation hazard symbol

  • The universal radiation symbol is important, so people that speak any language can still understand its meaning

Radiation Detectors

  • Radiation can be detected by a Geiger-Müller tube, or a geiger counter
  • Geiger-Müller tubes are simple devices that detect the presence of the ions created by radiation entering the tube
  • Connecting the tube to a counter allows the amount of radiation to be determined

Geiger-Counter, IGCSE & GCSE Physics revision notes

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

  • The amount of radiation given off by an isotope each second is known as its activity and is measured in becquerels (Bq)
  • An activity of one becquerel means that there is one decay per second

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Ashika

Author: Ashika

Expertise: Physics Project Lead

Ashika graduated with a first-class Physics degree from Manchester University and, having worked as a software engineer, focused on Physics education, creating engaging content to help students across all levels. Now an experienced GCSE and A Level Physics and Maths tutor, Ashika helps to grow and improve our Physics resources.