Uses and risks of radiation

GCSE Physics

Radiation can … living cells and …. atoms and … within them. This can lead to minor …….. damage

Radiation can … living cells and …. atoms and … within them. This can lead to minor …….. damage

enter, ionise, molecules, tissue

….. doses cause …. damage without killing the cells. This can give rise to … cells which divide uncontrollably. This is c…..

lower, minor, mutant, cancer

Higher doses tend to kill cells c…….. , causing radiation s…….. (leading to vomiting, tiredness and hair loss) if a lot of cells get batted at once

completely, sickness

What is gamma radiation used for in medicine?

Medical tracers and to kill cancerous cells

Why is gamma radiation used in medicine?

It has a short half-life so it can quickly be emitted out of the body without too much ionisation.

Smoke Detectors

Smoke alarms contain a weak source of Americium-241
Alpha particles ionise the air molecules, creating positive and negatively charged ions.
Two plates inside the detector create a flow of ions.
When the smoke enters the detector, it disrupts the flow of ions, triggering the alarm.
It has a long half-life so it does not need to be replaced very often.

Sterilising

Gamma rays can be used to kill bacteria, as it damages the cell of the bacteria, causing it to die. It also has a long half-life.

Radioactive tracers

A small amount of Iodine-123 is injected into the patient and after 5 mins 2 Geiger counters are placed on the body, tracking its progress through the body.
It is very safe as only gamma rays are emitted and it does not cause much ionisation due to the short half-life.

Checking Welds

If a gamma source is placed on one side of the welded metal, and a photographic film on the other side, when gamma rays are emitted, weak points or air bubbles will turn up on the film, like an X Ray.
It is a non-invasive process and is used to make sure new buildings are safe.

Contamination

Unwanted presence of materials containing radioactive atoms. The hazard from contamination is due to the decay of the contaminating atoms, for example, waste from a nuclear power plant.

Irradiation

Something is exposed to a radioactive source. It does not mean they are CONTAMINATED.