Radioactivity

Radiation, radioactivity, particles in atoms, what is radiation, different types of radiation etc.

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  • Created by: Tiula
  • Created on: 10-04-10 09:59

Alpha Radiation

Alpha Radiation

  • a helium nucleus
  • charge +2
  • slow, heavy
  • strongly ionising
  • weakly penetrating
  • stopped by paper, skin etc.
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Beta Minus Radiation

Beta - Radiation

  • an electron
  • charge -1
  • light, fast
  • moderately ionising
  • moderately penetrating
  • stopped by thin metal
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Positron Radiation

Beta + Radiation

  • a positron
    • the antimatter of an electron. Identical, but with an opposite charge.
    • when it meets an electron, they both annihilate. Positrons are not very penetrating because they will soon meet an electron and annihilate.
  • charge +1
  • light, fast
  • moderately ionising
  • not very penetrating (see above)
  • stopped by electrons
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Gamma Radiation

Gamma Radiation

  • electromagnetic wave
  • charge 0
  • no mass, very fast
  • weakly ionising
  • very penetrating
  • stopped by thick lead
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Neutron Radiation

Neutron Radiation

  • a neutron
  • charge 0
  • moderately fast and heavy
  • not directly ionising
    • although it doesn't ionise in itself, it can become absorbed by nuclei, which may then become radioactive
  • very penetrating, sometimes more than gamma
  • hard to detect because they're not affected by charged objects
    • detected by looking for nuclear decays from the nuclei that absorb them.
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Types of Radiation

If there are too many neutrons:

Beta minus - a neutron becomes a proton in the nucleus. Atomic no. increases by 1 and an electron is formed.

If there are too few neutrons:

Beta plus - a proton becomes a neutron in the nucleus. Atomic no. decreases by 1 and a positron is formed.

CONTINUED:

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Types of Radiation

If the nucleus is too heavy:

Alpha - the mass no. decreases by 4, the atomic no. decreases by 2. An alpha particle is formed.

If there is too much energy:

Gamma - sometimes, after alpha or beta decay there is too much energy in the nucleus, which is emitted on its own. You never get just a gamma ray.

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