Radiation was initially classified as alpha, beta and gamma to distinguish between their different properties.
Now we know that these particles are actually helium nuclei, electrons and photons. Is it time to drop the Greek labels?
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Detecting radiation - the ionisation chamber
Radioactive isotopes release alpha, beta and gamma particles. These ionise a gas by knocking electrons off the atoms. This makes the gas able to conduct electricity, which can be used to detect the particles.
Ionising radiation is stopped by the following materials:
- alpha - paper
- beta - aluminium
- gamma - lead
Stretch for 7
Alpha particles are helium nuclei. Alpha radiation results in the loss of 2 protons and 2 neutrons.
Beta radiation is the electrons released when neutrons change to protons.
Gamma radiation consists of high-energy photons.
The energy spectrum of beta particles indicates that they have a continuous spread of possible energies. This means that there must be another particle sharing the energy: the neutrino.
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