DANGER FROM RADIATION
Alpha, beta and gamma are all ionising radiation (break up molecules into smaller bits called ions)
Ions can be very chemically reactive and so in humans ionising radiation can cause serious damage to the cells in our body
A high dose of radiation tends to kill cells outright, causing radiation sickness.
Lower doses tend to damage cells without killing them
Irradation - Being exposed to radiation WITHOUT coming into contact with the source. The damage to the body STOPS as soon as you leave the radioactive area
Contamination - "Picking up" some radoactive material (breathing it in, drinking contaminated water, getting it on your skin). You'll STILL be exposed to the radiation once you've left the radioactive area
Radiation dose is meausured in sieverts (Sv) or millisieverts (mSv) . It takes into account the type and amount of radiation you've been exposed to.
People who are at a higher risk of radiation exposure include:
-Workers in nuclear power plants
-Airline staff (radiation comes from cosmic rays)
USING IONISING RADIATION
Low level radiation is everywhere which constantly irradates and contaminates us. It comes from:
1. NATURAL RADIOACTIVE ELEMENTS (the air, the soil, living things)
1. SPACE (cosmic rays) - comes from the sun
3. HUMAN ACTIVITY - From nuclear explosions or waste from nuclear power plants
Radioactive sources are considered to be safe when the radiation they are emitting is about the same level as the background radiation.
The half life of the source gives an idea of how long it will take for this to happen
Uses of ionising radiation
- High doses of gamma rays will kill all living cells (treats cancer)
- Have to be directed carefully and at just the right dosage in order to not kill healthy cells
- However a fair bit of damage is inevitably done to normal cells which leaves the patient feeling very ill
- "Benefit outweighs the risk"
STERILISING MEDICAL EQUIPMENT
- Gamma rays sterilise equipment by killing all the microbes
- This is better than boiling instruments which might be damaged by high temperatures
- You need to use a strongly radioactive source that has a long half life, so it doesn't need replacing too often
Uses of ionising radiation
- Food can be sterilised in the same way as medical instruments (killing all the microbes)
- This keeps the food fresher for longer
- The food isn't radioactive after so its safe to eat
- Alwasy labelled
- Tracers = Radioactive molecules that can be injected into people. Their progress around the body is followed using an external detector. They can detect cancer.
- Isotopes used as tracers must be gamma or beta emitters so the radiation passes out of the body
- They shoud have a short half life so that the radioactivity inside the patiet quickly disappears