Half life and uses of radiation

What is half life defined as?

the time it takes for the activity of a radioactive source to halve, or the time it takes for half the radioactive nuclei to decay.

Name 5 uses for radioactive materials

1. Tracer

2. Treating cancer inside the body

3. Treating cancer from outside the body

4. Monitoring the thickness of paper or foil

5. Smoke detectors

What is a tracer?

A radioactive material is injected into the body and cameras are used to make an image of where the radiation is. This can take very detailed images of inside the body.

What type of radiation is used in a tracer?

Gamma

What is the half life of a tracer?

Short

What is a treating cancer inside the body?

A radioactive material is placed inside the tumour to kill the cancer cells.

What type of radiation is used in treating cancer inside the body?

Beta

What is the half life of treating cancer inside the body?

Short

What is treating cancer from outside the body?

Radiation is aimed at the tumour from outside the body.

What type of radiation is used in treating cancer from outside the body?

Gamma

What type of half life is used in treating cancer from outside the body?

Long

What is monitoring the thickness of paper or foil?

A source is placed on one side of a sheet of paper or foil and a detector on the other side. If the count is too low, not enough radiation could penetrate and the paper is too thick.

What type of radiation is used in monitoring the thickness of paper or foil?

Beta

What half life is used for monitoring the thickness of paper or foil?

Long

What is smoke detectors?

Radiation in the detector ionises the air, which creates a current. If there was smoke in the detector it would block the radiation and the current would change, setting off the alarm.

What is the radiation used in smoke detectors?

Alpha

What is the half life used in smoke detectors?

Long