Using Radiation

• Examples of uses of radioactivity

  Household fire alarms, irradiating food, sterilisation of equipment, tracing and gauging thicknesses of materials, diagnosis and treatment of cancer
• How do smoke alarms work?

  A radioactive substance in the alarm emits alpha radiation, ionising the air in the detector and causing a current to flow between the plates. When smoke interferes with the radiation, the air is no longer ionised so can’t flow, triggering the alarm.
• What is the role of beta radiation in tracers?

  The tracer is inserted into your body, targeting a specific part. The radioactive substance in the tracer releases beta radiation, which can be detected by external machines.
• How is beta radiation used to determine thickness?

  A beta source is placed above the material and a detector is placed below it, if there is an increase in radiation detected too much radiation is passing through the material. If there is a decrease then the material blocks too much radiation, so it is too thick.
• Why is ionising radiation dangerous?

  It can damage tissue and kill cells, it can can cause cell mutations
• What precautions should people take when using ionising radiation?

  Avoid handling the source directly (use tongs), wear radiation protective clothing, keep the radiation in lead containers and keep exposure time to minimum.
• Why does a longer half life make a substance more dangerous?

  It remains highly radioactive for longer.
• What precautions are taken to reduce harm for doctors and patients using ionising radiation?

  Only a small dose is given, it has a short half life so won‘t remain highly radioactive for long, doctors and patients wear protective clothing
• What is radioactive contamination?

  The presence of unwanted radioactive nuclei on other materials.
• What is irradiation?

  The process of exposing a material to nuclear radiation, the material does not become radioactive
• Isotopes are using in Positron Emission Tomography (PET), what is important about their production?

  They must be produced near the hospital because the isotopes used have a short half life so must be used soon after production.