Radiation Flashcards
Definitions from the N5 Radiation sub-unit
What is the charge on a Proton?
Positive
What is the charge on a Neutron?
Neutral / No charge
What is the charge on an Electron?
Negative
What is meant by the “Atomic number” of an atom?
Number of Protons within the atomic nucleus
What is meant by the “Mass number” of an atom?
Number of Protons & Neutrons within the atomic nucleus
What is meant by the “Ionisation” of an atom?
When an atom loses or gains an electron to form a charged particle known as an ion.
What is the composition of Alpha radiation?
Particle : 2 protons & 2 neutrons
What is the composition of Beta radiation?
Particle : High energy electron from the nucleus
What is the composition of Gamma radiation?
Wave : High energy Electromagnetic radiation
How does a “GM tube and counter” work to detect radiation?
When radiation enters through the thin Mica window, the radiation ionises the gas within the tube. These ions allow a current to flow between the casing and the central electrode, which is registered by the counting circuit.
How does a “Film Badge” work to detect radiation?
A small piece of photographic film is sealed into the back of the badge, and has different material shields placed in front of it.
This allows the type of radiation being detected to be determined, by analysing which sections have darkened due to radiation.
How does a “Cloud Chamber” work to detect radiation?
When radiation passes through the vapour, atoms in the vapour become ionised. The ionised vapour acts as condensation nuclei and
droplets form in the air along the path the radiation took.
What is meant by the “Activity” of a radioactive source?
A measure of how many atoms decay radioactively every second.
What is meant by the “Half-Life” of a radioactive source?
The length of time for the activity of a radioactive source to decrease by half.
What is meant by “Absorbed Dose”?
A measure of how much Energy is absorbed per unit mass.
What is meant by “Equivalent Dose”?
The Absorbed Dose value, multiplied by a ‘radiation weighting factor’ to take into account the level of ionisation.
What is meant by “Equivalent Dose Rate”?
A measure of how much Equivalent Dose recieved per unit time.
Give a use of Radiation.
- Treatment of Cancer
- Sterilisation of Medical Equipment
- Radioactive Tracers
- Pipeline Leak Detection
- Carbon Dating
State a source of natural Background Radiation.
- Radon gas from the ground.
- Rocks & Building materials.
- Food & Drink
- Cosmic Rays
State a source of artificial Background Radiation.
- Medical uses of radioactivity.
- Nuclear power
- Nuclear Weapons testing
- Industrial uses of radioactivity
What is meant by “Fission”?
A large nucleus splitting into two or more smaller nuclei, releasing energy.
What is meant by “Fusion”?
Two small nuclei join together to make a larger nucleus, releasing energy.
State a benefit for using Nuclear Fusion as an energy source.
- Fuel source is hydrogen from water.
- Waste product is helium which is not radioactive.
- Produces more energy than fission
- Reactors have no risk of ‘meltdown’.
State a drawback for using Nuclear Fusion as an energy source.
- Maintaining temperature is very difficult.
- Containing the plasma is difficult as all physical containers would melt.
- At present, reactors not efficient enough to be commercially used.
What can block “Alpha particles”?
A sheet of paper or a few cms of air.
What can block “Beta particles”?
A few mm of aluminium.
What can block “Gamma rays”?
A few cm of lead.
