Radiation ☢️

• Alpha, beta, gamma and X-Rays are all ionising radiations that can do damage to the cells of the body.
• Alpha particles are made from two protons and two neutrons, have a charge of +2, and when they travel through materials they collide with atoms and lose their energy.
• Beta particles are made up of a single electron, have a charge of -1, and when they travel through materials they also collide with atoms and lose their energy.
• Gamma rays are waves carrying energy, have no charge, and when they travel through materials they collide less frequently with atoms than alpha and beta particles.
• Nuclear reactions either involve atoms splitting apart, fission, or 2 or more atoms joining to make one, fusion.
• In the process of fission, a red neutron, A, collides with a heavier, unstable nucleus, B, causing it to break apart.
• The products of the reaction are two smaller nuclei and some extra neutrons, and they have less mass than the neutron and nucleus, B.
• The lost mass is converted into kinetic energy as the products fly apart, a process called fission.
• The neutrons released in fission can collide with other nuclei and cause them to split too, this ongoing sequence is called a chain reaction.
• In a nuclear reactor, an uncontrolled chain reaction would potentially become catastrophic.
• To get the reaction to take place at a manageable rate, the reactor has control rods and moderators that absorb and slow the neutrons.
• The equivalent dose rate is found using the expression H` = h / t.
• Natural sources of radiation include radioactive gases in the air and buildings, rocks of the earth, and in food and bodies.
• The government sets annual effective dose limits to protect the public and workers exposed to radiation.
• The absorbed dose indicates the energy absorbed by a tissue, while the equivalent dose puts a weighting on that dose according to the type of radiation.
• Workers are supported by monitoring and health checks, and to make the industries viable, the government says they can be exposed to higher levels of equivalent dose.
• The equivalent dose is the biological risk caused by the energy and the radiation type, measured in Sieverts (Sv).
• The background radiation varies depending on the geology of where you are.
• Artificial sources of radiation include medical uses, weapons testing, the nuclear industry, and sundries such as work, flights, etc.
• Most exposures are measured in microSieverts, μSv, ( × 10^‑6 Sv) or milliSieverts, mSv, ( × 10^‑3 Sv).
• Certain foods, such as brazil nuts, bananas, potatoes, and carrots also have higher levels of radiation and contribute to the amount of radiation someone receives.
• In the UK, the average background radiation is around 2.2 mSv a year.
• The equivalent dose is calculated from the expression: H=DwR.
• High doses can also cause radiation burns, and/or rapid fatality through acute radiation syndrome.
• All living things are made up of cells.
• Using a radiation source and detector, we can set the detector to give feedback if the paper allows too much or too little radiation through.
• Rontgen discovered that X-rays pass through materials such as skin and muscle but are absorbed by denser materials such as bone and metal.
• Nuclear reactors use ionising radiations to generate heat and power.
• Controlled short exposure high doses are used for medical imaging and radiotherapy.
• The radiotherapy may be used to relieve symptoms for patients with incurable cancers.
• Exposure to high doses of radiation from laboratory or medical sources can cause the cells of tissues and organs to be killed until the point that the tissues and organs no longer function.
• Ionising radiation is harmful, but its effects are seen over both the short and long term.
• Knowing how much should be absorbed by the correct thickness of metal allows us to determine whether a piece of metal is the correct thickness.
• The feedback changes the pressure applied by the roller to correct the thickness.
• Metal structures can fail due to weak components, leading to death or massive costs.
• This process is instantaneous and keeps the paper thickness within tolerance.
• Paper can absorb alpha radiation, if it is suitably thick.
• Ionising radiations are absorbed by metals, but not all of them are absorbed instantly.
• Radiation can be used to cure cancer, either on its own or as part of a treatment package using surgery and/or chemotherapy.
• A radiation oncologist uses ionising radiation (such as X-rays or radionuclides) to treat cancer.