Radioactivity Essay

639 WordsApr 1, 20093 Pages
Concepts: 6 protons (we can deduce this from the proton number 12 nucleons à 6 protons and 6 neutrons No. of protons = no. of electrons Therefore… no. of electrons = 6 4 nucleons 2 protons and 2 neutrons and of course… 2 electrons But we don’t only have this We also have this These two are called isotopes of carbon! Definition: Isotopes are atoms of the same element which have different number of neutrons Examples: Hydrogen exists in three isotopes; protium, deuterium and tritium Uranium which is used in nuclear power plants exists as three main isotopes; uranium uranium-238, uranium-235 and uranium-234 *1 All elements have more than one isotope! *2 Many of these isotopes are unstable. *3 This means that the nucleus breaks up into smaller nuclei. *4 When this happens alpha(α )– particles, Beta (β)-particles and gamma (γ)- rays may be emitted from the nucleus. *5 This is called radioactive decay Detecting radioactivity The Geiger-Muller tube (G-M tube) G-M tube and the Geiger counter *1 A potential difference of about 400 V is applied between the anode and the cathode. *2 In between the anode and the cathode there’s argon gas at low pressure *3 The end of the tube is sealed by mica window thin enough to allow alpha particles to pass into the tube as well as beta and gamma radiation. *4 When an α (alpha) or β (beta) particle enters the tube (or gamma radiation) the argon gas becomes ionised. *5 This causes the flow of ions between the electrodes and a pulse of current flows in a circuit that is part of the G-M tube. *6 This circuit is either connected to a scaler or a ratemeter. A scaler counts the pulses and shows the total on a display. A

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