P6.2 Flashcards
What makes up the different background radiation that we are exposed to
Ground and buildings - 14%
Cosmic rays - 10%
Other - 0.2%
Radon gas (rocks) - 50.0%
Food and drink - 11.5%
Artificial sources - 14.3% (medical uses 14.0%, nuclear power 0.1%, nuclear weapons resting 0.2%)
What happens when contamination occurs
Contamination happens when you take radioactive material inside your body or it’s on your skin. When it’s internally contaminated, you can’t remove the radioactive material inside you.
What is radiation
Radioactive material outside your body but radiation can travel inside.
Why do radioactive materials not pose much of a risk in terms of cancer
The risk of getting cancer is very low if your aren’t exposed to too much radiation. As your body can repair any damage from small doses of radiation.
What are radioactive tracers
Doctors inject with isotope
Radioactive isotope absorbed by organs
Detected by gamma camera
Used to image organs
What do doctors have to do when choosing isotopes
half life can’t be too short as the tracer decays before the gamma camera can use
Can’t be too long so tracer continues to emit radiation increasing risk of cancer.
What are gamma knives
Radioactive material emitting gamma rays.
Gamma rays focused on tumour killing it whereas other healthy tissues receives a small amount.
What is nuclear fission
When a large nucleus can split into fragments and emit neutrons.
What is needed for nuclear fission to occur
Fission is more likely to happen when the nucleus absorbs a neutron and splits and produces two smaller nuclei and two or three neutrons.
How does nuclear fission produce heat
All the fission products are moving and they collide with and heat up the matter around them and is used in power stations.
What is needed to start fission reactions
You need a neutron to start a fission reaction but the reacting also produces neutrons. Those neutrons start other fission reactions. You can start a chain reaction.
What happens in a nuclear reactor
There are billions of fission reactions per second so a huge amount of energy is released.
How do they control chain reactions in a power station
By using materials to absorb some of the neutrons.
What is nuclear fusion
Lighter nuclei can join together to make more stable nuclei is in a process called nuclear fusion.
What is the problem with trying to join nuclei together
Is that they have the same charge, so they repel eachother.
