Radiation and Particles Flashcards
(26 cards)
Alpha
- Helium Nucleus
- Blocked by few cm air or paper
- Highly Ionising
- Slow moving
Beta
- Fast moving electron
- Blocked by thin aluminium
- Moderately ionising
- Moderate speed
Gamma
- Electromagnetic wave
- Blocked by thin lead or concrete
- Low ionising
- Fast Moving
Radioactivity is measured in…
Bequerel
Device used to measure Radioactivity
Guiger Muller Tube
Background Radiation
Radiation that exists around us all the time
Background Radiation Examples
- Nuclear waste/weapons
- Medical X-rays
- Rocks
- Sun
- Food
Half-Life
Time taken for half of the radioactive substance to decay
Contamination
When unwantanted radioactive atoms come in contact with a material, the material becomes radioactive
Irradiation
A material is exposed to unwanted radioactive source, the material DOES NOT become radioactive
Uses of Radiation
- medical tracers
- cancer treatment
- food and equipment sterilisation
- industries
Medical tracers
Beta or gamma injected into the body
can be detected extrenally
Cancer treatment
radiotherapy kills cancer cells and stops them dividing
Food and equipment sterilisation
gamma kills microbes and bacteria
Industries
detects leaks in underground pipes
Risks of Radiation
- cell tissue damage
- radioactive waste
Cell tissue damage
if alpha enters the body it is very dangerous - causes cell mutations
Radioactive waste
- long half-life
- sealed in thick lead/concrete box and stored deep underground
- Plate movement causes leaks - contaminates groundwater, soil, plants
Nuclear Fission
- slow moving neutron is absorbed by Uranium-235
- Uranium-235 nucleas splits forming two daughter nuclei
- Releases a small number of neutrons
Chain Reaction
- nuclear fission releases neutrons
- neutrons collide with another Uranium-235 and undergo fission
- releases more neutrons
- this process repeats
Control Rods - Boron
Absorb Excess neutrons
Moderator - Graphite
Slows down neutrons
Shielding - concrete or lead
absorbs ioniding radiation
Nuclear Fusion
- Two nuclei collide and fuse together to form a large nucleus
- Energy released
