Uses of Radioisotopes
There are lots of different uses of radioisotopes in industry, in medicine
and even in our homes.
When choosing an isotope one must consider 2 things
What kind of radiation it emits
Its half life
The reason should become clear from the examples below.
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Smoke alarms
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Alpha particles travel through a gap ionising the air. When smoke enters
the detector they block some of the alpha particles so less ions are
detected. This triggers an alarm. Isotope used is an alpha source with a
half life of at least a few years. |
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Thickness Monitoring
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How much beta radiation gets through the paper depends on its thickness.
We can therefore monitor the thickness as soon as the paper is made and make
adjustments to the roller pressure if needed. Isotope used is a beta
source with a half life of at least a few years. |
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Medical Tracers
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One technique involves injecting patients with an isotope which is
absorbed by bones when they are healing. The gamma rays are detected and a
computer is used to build up a 3D picture of the patient's bones, showing
areas where healing is taking place. Isotope used is a gamma emitter with
a half life of a few hours. |
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Dating
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Archaeologists can measure the amount of radiation emitted by old things
and work out how much Carbon 14 they contain. This will tell them how old it
is. Carbon 14 has a half life of 5.7 thousand years.
Geologists measure the amount of radiation given off by certain rocks.
They have worked out the age of the Earth from this.
Uranium 238 has a half life of 4.5 billion years. |