Radiation Flashcards
The three types of nuclear radiation
Alpha, Beta, Gamma
What is gamma radiation?
Electromagnetic radiation from the nucleus
Which type of radiation is the most ionising?
Alpha
What is the range in air for alpha, beta and gamma radiation?
Few cm
1m
Unlimited respectively
What materials stop alpha, beta and gamma radiation?
Sheet of paper
Thin aluminium sheet
Thick lead/concrete
Which type of nuclear radiation does not cause a change in the structure of the nucleus when it is emitted?
Gamma
What is radioactive decay?
The rate at which a source of unstable nuclei decays
What unit is used to measure the activity of a radioactive source?
Becquerel (Bq)
What is ‘count-rate’?
Number of decays recorded each second
by a detector e.g. Geiger-Muller tube
What is meant by half-life of a radioactive source?
Time taken for half of the unstable nuclei to decay
What is irradiation?
Exposing an object to nuclear radiation
What is radioactive contamination?
The unwanted presence of substances containing radioactive atoms on or in other materials
Where does background radiation come from?
Rocks
Cosmic Rays
Fallout from nuclear weapon testing
Nuclear accidents
Why are gamma-emitting sources used for medical tracers and imaging?
Gamma rays pass through the body without causing too much damage as they aren’t strongly ionising
What is nuclear fusion?
When two light nuclei join to make a heavier one
