Waves & Radiation: Radiation Flashcards
What is ‘ionisation’?
Ionisation is the addition or removal of an electron from a neutral (uncharged) atom.
What are the three types of ‘ionising radiation’?
The three types of ‘ionising radiation’ are alpha, beta, and gamma.
Describe the properties of alpha particles.
What are they? What is their absorption? Ionisation rate?
Alpha particles are 2 neutrons, and 2 protons - therefore they are positively charged.
They can be described as the nucleus of helium.
Alpha particles can travel roughly 5cm through air. They will also be stopped by a sheet of paper.
These are far more ionising than beta or gamma.
Describe the properties of beta particles.
What are they? What causes them? What is their absorption? Ionisation rate?
Beta particles are fast moving electrons. They come from within the nucleus of an atom.
They are caused when a neutron breaks up into a positively charged proton, and negatively charged electron.
Beta particles can travel several metres through air. They will be stopped by a thin sheet of aluminium.
Beta particles are less ionising than Alpha.
Describe the properties of gamma rays.
What are they? What causes them? What is their absorption? Ionisation rate?
Gamma rays have no mass or charge, and carry energy leaving the nucleus in a more stable state.
Gamma rays are caused by energy changes in a nucleus.
Gamma radiation can travel several hundred metres in air. High levels of gamma can only be stopped by many metres of concrete.
Gamma rays cause less ionisation than alpha or beta particles.
Describe a Medical use of radiation.
Due to it being able to destroy cells, radiation can be used in the treatment of cancer.
Gamma rays from a radioactive source, such as ‘cobalt-60’ can be centred on the cancerous tumour to kill it.
Surrounding healthy tissue does not receive much radiation as it is fixed on the tumour.
Describe a use of radiation in industry.
Radioactive tracers can be used in industry to find leaks or blockages in underground pipes.
These tracers give off particles that can be detected and turned into an image to help find these leaks/blockages.
How can we detect radiation through a Geiger-Muller (GM) tube?
If alpha, beta, or gamma enter the tube, ions are produced resulting in a small current flow.
The current is amplified and a counter counts the number of events giving an indication of the radioactivity.
How can we detect radiation through a photographic film badge?
Photographic film blackens or darkens when it is exposed to radiation. The more radiation absorbed, the darker the film becomes.
