radiation

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ionising radiation

ionisation: the loss or gain of electrons to form an ion

ionising radiation Radiation that is able to remove electrons from atoms or molecules to produce positively-charged particles called ions (ion is just an electrically charged particle not necerssarily positive)

ionising radiation is emitted from unstable nuclei of radioactive atoms: ALPHA BETA GAMMA

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Alpha particle

same as a helium atom: 2 protons 2 neutrons

Alpha have a mass of 4 ( protons+ neutrons) and a charge of +2 (protons are positive)

When an (http://www.darvill.clara.net/nucrad/images/alphasymbol.jpg)-particle or (http://www.darvill.clara.net/nucrad/images/betasymbol.jpg)-particle ionises an atom, it slows the particle down.

This is one reason that alpha particles have such a low penetrating power - they ionise other atoms strongly and thus get slowed down a great deal.

alpha gains electrons when ionising as they attract the negative electrons strongly through ionising.

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beta particles

beta particles are formed when a radioactive nucleus degenerates and a neutron from the unstable nucleus splits into a proton and an electron and the electron is spat out leaving behind the proton.

this happenes when there is too many neutrons within a nucleus compared to the protons and so they degenerate.

beta travel at high speed and have a moderate penetration range (further than alpha but not as far as gamma)

quite ionising also

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gamma rays

if a nuclei needs to get rid of excess energy it can emit gamma rays

gamma rays are energy ONLY and so have no charge or mass

travel a long way and can pass through air .... thus they are weakly ionising because they tend to pass staright through rather than colliding with atoms, they can eventually hit something and do damage.

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