Uses of Radiation
Smoke Detectors
Smoke alarms contain a weak source made of Americium-241.
Alpha particles are emitted from here, which ionise the air, so that the air conducts electricity and a small current flows.
If smoke enters the alarm, this absorbs the a particles, the current reduces, and the alarm sounds.
Am-241 has a half-life of 460 years
Sterilising
Even after it has been packaged, gamma rays can be used to kill bacteria, mould and insects in food. This process prolongs the shelf-life of the food, but sometimes changes the taste.
Gamma rays are also used to sterilise hospital equipment, especially plastic syringes that would be damaged if heated.
Radiation can not only kill cells but also damage DNA: radiation is ionising. It turns the molecules in DNA into ions and makes them reactive.
Radioactive Tracers
The most common tracer is called Technetium-99 and is very safe because it only emits gamma rays and doesn't cause much ionisation.
Radioisotopes can be used for medical purposes, such as checking for a blocked kidney.
To do this a small amount of Iodine-123 is injected into the patient, after 5 minutes 2 Geiger counters are placed over the kidneys.
Also radioisotopes are used in industry, to detect leaking pipes. To do this, a small amount is injected into the pipe. It is then detected with a GM counter above ground.
Checking Welds
If a gamma source is placed on one side of the welded metal, and a photographic film on the other side, weak points or air bubbles will show up on the film, like an X-ray.
Cancer Treatment
Because Gamma rays can kill living cells, they are used to kill cancer cells without having to resort to difficult surgery. This is called "Radiotherapy", and works because cancer cells can't repair themselves when damaged by gamma rays, as healthy cells can.It's vital to get the dose correct - too much and you'll damage too many healthy cells, too little and you won't stop the cancer from spreading in time. Long exposure is prevented by having multiple sources spinning around the patient so that they never receive a harmful dose, except at the tumour site.
Some cancers are easier to treat with radiotherapy than others - it's not too difficult to aim gamma rays at a breast tumour, but for lung cancer it's much harder to avoid damaging healthy cells. Also, lungs are more easily damaged by gamma rays, therefore other treatments may be used.
Smoke alarms contain a weak source made of Americium-241.
Alpha particles are emitted from here, which ionise the air, so that the air conducts electricity and a small current flows.
If smoke enters the alarm, this absorbs the a particles, the current reduces, and the alarm sounds.
Am-241 has a half-life of 460 years
Sterilising
Even after it has been packaged, gamma rays can be used to kill bacteria, mould and insects in food. This process prolongs the shelf-life of the food, but sometimes changes the taste.
Gamma rays are also used to sterilise hospital equipment, especially plastic syringes that would be damaged if heated.
Radiation can not only kill cells but also damage DNA: radiation is ionising. It turns the molecules in DNA into ions and makes them reactive.
Radioactive Tracers
The most common tracer is called Technetium-99 and is very safe because it only emits gamma rays and doesn't cause much ionisation.
Radioisotopes can be used for medical purposes, such as checking for a blocked kidney.
To do this a small amount of Iodine-123 is injected into the patient, after 5 minutes 2 Geiger counters are placed over the kidneys.
Also radioisotopes are used in industry, to detect leaking pipes. To do this, a small amount is injected into the pipe. It is then detected with a GM counter above ground.
Checking Welds
If a gamma source is placed on one side of the welded metal, and a photographic film on the other side, weak points or air bubbles will show up on the film, like an X-ray.
Cancer Treatment
Because Gamma rays can kill living cells, they are used to kill cancer cells without having to resort to difficult surgery. This is called "Radiotherapy", and works because cancer cells can't repair themselves when damaged by gamma rays, as healthy cells can.It's vital to get the dose correct - too much and you'll damage too many healthy cells, too little and you won't stop the cancer from spreading in time. Long exposure is prevented by having multiple sources spinning around the patient so that they never receive a harmful dose, except at the tumour site.
Some cancers are easier to treat with radiotherapy than others - it's not too difficult to aim gamma rays at a breast tumour, but for lung cancer it's much harder to avoid damaging healthy cells. Also, lungs are more easily damaged by gamma rays, therefore other treatments may be used.
Background Radiation
We are constantly being bombarded y nuclear radiation. Below is a pi chart showing some of the sources of this radiation.