Radioactive Decay Flashcards
What are Alpha particles
Two neutrons and two neutrons
A helium nuclei
When are alpha particles emitted
When a nucleus has too many protons
What can alpha radiation do (4)
Travel a few cms in air
Be absorbed by a sheet of paper
Be stopped quickly and does not penetrate very far into materials
Strongly ionising due to its size
When is alpha radiation used?
Smoke detectors:
Alpha radiation ionises air particles-causing a current to flow
If there is smoke in the air, it binds to the ions-meaning the current stops and the alarm sounds
What is ionisation power
The ability to be able to knock an electron from an atom-turning it into an ion
What are beta particles
Fast moving electrons with no mass and a charge of -1
What are the characteristics of beta particles (3)
Moderately ionising and penetrating moderately far into materials
Have a range in air of a few cms
Are absorbed by a sheet of aluminium
When are beta particles emitted (2)
When a nucleus has too many neutrons and for every beta particles emitted, a neutron in the nucleus turns to a proton and an electron- the proton remains and the electron is fired out
What are gamma rays
Waves of electromagnetic radiation
What are the characteristics of gamma particles
Penetrate far into materials and are weakly ionising
Travel a long distance in air
Are absorbed by thick sheets of lead or metres of concrete
When are beta emitters used (4)
To test the thickness of sheets of metal:
The particles are not immediately absorbed by the material (like alpha)
Do not penetrate as far in materials as gamma rays
Slight variations in thickness affect the amount of radiation passing through the sheet
When are gamma rays used
Medical tracers:
The person ingests the radiation-which can then be tracked around the body (a short life of roughly 6hrs is used which allows the food to be digested and the person does not stay radioactive for a long period of time)
Used to treat cancer and sterilise medical equipment or food (within its packaging):
Gamma can kill living cells
