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Detection of Ionizing Radiation
- Photographic film: The more radiation absorbed by the photographic film, the darker the film becomes. This is worn by people who work with radiation to monitor the level of radiation exposure.
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- Geiger-Müller tube: Gas is stored in the tube at low pressure. When ionizing radiation enters the tube, gas particles will become ionized, making it possible to flow a pulse of current in the electrode. Counting circuit measures the level of radiation entering the tube.
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Background Radiation
Background radiation is radiation present in the environment which is not due to intentional introduction of radiation. Some sources of background radiation are:
- Cosmic rays travelling from space to Earth
- Some rocks that give off radioactive radon gas
- Radioactive food and drinks
- Buildings and the ground
- Nuclear power and weapons test
- Medical sources such as X-rays
Uses of Radioactivity
- Archaeological dating: Living plants absorb small amount of radioactive carbon-14, and carbon-14 starts to decay after the plant dies. By measuring the activity of carbon-14 in an ancient relic, scientists can estimate the age.
- Sterilization: Gamma rays are used to kill any bacteria or parasites and sterilize equipment or food.
- Cancer treatment: Cobalt-60 decays by emitting gamma rays, and gamma rays can kill cells in malignant tumors.
- Thickness monitoring: Beta particles can be used to monitor thickness of thin metal sheets.
- Tracers in medicine: Using radioactive isotopes of elements that easily accumulate in a specific site of the body can help to monitor the functions of the body.
Dangers of Radioactivity
- Contamination occurs when a radioactive source is introduced into the object. The contaminated object will become radioactive.
- Irradiation occurs when an object is exposed to a radioactive source outside of the object. The object does not become radioactive in this case.
- Exposure to radiation can cause mutations in the DNA, causing cancer, or damage and kill cells by ionizing the cell membrane.
Reducing Risks of Radiation
- Always wear protective clothing, such as lead-lined suits and gloves, when working with radiation.
- Wear film badges containing photographic film to monitor the level of exposure to radiation.
- Nuclear power plants produce waste that may remain radioactive for thousands of years. These waste are tightly sealed in lead-lined containers and then buried deep underground. The site for burial should be impereable to water and have no earthquake or volcanic activity.