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Topic 6 ­ using radioactive materials

Background radiation

Most background radiation comes from natural sources while
artificial background radiation comes from medical examinations.
The radioactivity of a source is measured using half-life.

Background radiation is the low level radiation that's around us all
the time. Natural sources are:

source Type…

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Uses of radiation

Ionisation is when radioactive
materials ionise other materials and
turn the atoms into charged particles - ions. This can be a useful

Uses of alpha radiation

Alpha radiation is used in smoke detectors. Radioactive americium
releases alpha radiation which ionises the air inside the detector

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unit and adjusts the rollers to give the correct thickness. The
radioactive source must have a long half-life so that it doesn't decay
too quickly. It needs to beta because the paper will partly block the
radiation and if it all goes through or none, the reading will not

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A short half-life means the activity falls quickly because lots of the
nuclei decay quickly and a long half-life means the activity falls more
slowly because most of the nuclei don't decay for a long time.

The activity of a radioactive isotope is measured in Becquerel (Bq). 1
Bq is…

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Dangers of radioactivity

Ionising radiation can cause tissue damage and cell mutation. Alpha,
beta and gamma radiation enter the living cell and collide with
molecules which causes the molecules to break into smaller
fragment. As a result ionisation happens which leads to tissue
damage. Radiation affects DNA, causing mutations. These…

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Exposure times are limited
Keep source at arm's length to keep it as far from the body
as possible


Development of radioactive materials in 20th century led to
many workers death. The materials were new so people did
not realise they could be dangerous. The risks can be assessed…

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Public perceptions are negative ­ nuclear power dangerous
Worried that nuclear waste can never be disposed safely.
There is a danger of leaks and pollution of land, rivers and
oceans. Contamination of huge areas. People say the energy
generated is not worth the risk of nuclear waste accidents.


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