§4 Working with gamma radiation

• Natuurkunde
• Middelbare school
• havo
• Leerjaar 3

Learning objectives

• You can describe what the terms 'radioactivity' and 'half-life' mean.
• You can calculate the activity of a substance after N half-lives.
• You can determine the half-life from a graph of the activity against time.
• You can describe the three types of radiation that are emitted by radiactive substances.
• You can describe the penetrating power of the various types of radiation.
• You can describe how medical research is carried out using gamma radiation.
• You can explain the difference between contamination and irradiation and how they are applied.  

Little radiation has fallen on the black part of an X-ray.

1. Correct
2. Incorrect

You can describe what radioactivity is.

Radioactive substance

Ionising radiation

Radioactive radiation

Radioactive = emits radiation

Radioactive substance or ionising radiation

Naturally radioactive

1 hour in the Fukushima disaster area is equivalent to eating 104 bananas.

After 1896 we learned to develop artificially radioactive substances.

Brazil nuts are known to contain small amounts of radium, a naturally radioactive substance.

Background radiation in the NL

You can calculate the activity over time.

You can determine the half-life from a decay curve.

The amount of radiation from a radioactive source with a half-life of 50 minutes.

Exponential decay curve

Radioactive iodine has a half-life of 8 days.

After how many days is there less than 1.0% left of the original amount of radiation?

1. 40
2. 56
3. 48
4. 64

You can describe three types of radiation that radioactive substances can emit.

Three kinds of radiation

You can describe the penetrating power of the various types of radiation.

You can describe research with gamma rays.

Examinations using gamma radiation

• Making tracer
• Injecting tracer
• registering radiation
• analysing image of the organ 

A tracer is made in the laboratory

The tracer is injected in the body of the patient

The gamma camera registers the release of radiation

A false-colour image of a thyroid gland.

You can explain the difference between irradiation and contamination

Irradiation and contamination

Contamination

Contamination

irradiation

Irradiation

contamination

Protection

A container for transporting radioactive substances. The inner and outer walls are made of steel. Between them is a thick layer of lead.

You must wear a protective suit when taking samples of water that may potentially be radioactively contaminated.

What types of particle radiation are emitted by radioactive materials?