Radiation Flashcards
State one detector of gamma radiation
- Photographic film
- GM tube
- Bubble chamber
State one source of gamma radiation
- Stars
- Some radioactive substances (e.g. Cobalt 60)
State one use for gamma radiation
- Used as a tracer in medicine
- Used to treat cancer
- Sterilisation of surgical operating instruments
- Gamma rays kill microbes and are used to keep food fresher for longer. This is known as “irradiated” food
- Checking for cracks in aeroplane wings and joints
What are the 3 types of ionising radiation?
- Alpha
- Beta
- Gamma
What is alpha radiation?
It is a helium nucleus
(2 protons and 2 neutrons)
What is beta radiation?
A fast moving electron
What is gamma radiation?
It is a high frequency, high energy wave and part of the electromagnetic spectrum
What is meant by ionisation?
It is the gain or loss of an electron from an atom
Which is the most ionising radiation?
alpha
Which is the least ionising radiation?
Gamma
State 3 detectors if ionising radiation
- Photographic film
- GM tube
- Scintillation counter
What will absorb alpha radiation?
A few centimetres of air or a sheet of paper
What will absorb beta radiation?
A few millimetres of aluminium
What will absorb gamma radiation?
Several centimetres of lead
What is meant by shielding?
Shielding means having something that will absorb radiation between you and the source of the radiation
What will the amount of shielding required depend on?
The amount of energy the radiation has
How can you reduce your exposure to radiation when you are working with it?
- Limit the time you have the source out (only get it when you need it)
- Only handle using tongs
- Keep the source at arms length
- Wash hands before & after use
- Do not eat while handling it
- Wear lead lined gloves/ apron and safety goggles
What is meant by background radiation?
It is the radiation that is all around us
State a source of man-made background radiation
- Nuclear weapons testing
- Waste from the nuclear power industry
- Medical uses: having an x-ray, CT scan, etc
State a source of natural background radiation
- Cosmic rays: radiation from the sun and outer space
- Radon gas: from rocks underground
- Food: can be slightly radioactive because of the soil it has been grown in
What is meant by absorbed dose?
The energy absorbed per unit mass (of tissue)
What is equivalent dose?
It is a way of taking into account the absorbed dose and the type of radiation you are exposed to
What is the radiation weighting factor?
A number which takes into account the type of radiation you are exposed to
What is the link between the radiation weighting factor and the ionisation caused by a source?
The more ionising the radiation, the higher the radiation weighting factor