1. Characteristics of ionizing radiation

Radiation sources

Industrially, we use γ-rays from cobalt 60, more rarely from cesium 137 (for research), and accelerated electrons with energies of 10 MeV or less.

Accelerated electrons are not currently permitted in food.

γ-rays are electromagnetic waves with no mass or charge, and high penetrating power.

The γ rays emitted by cobalt 60 (energies of 1.17 and 1.33 MeV) induce the creation of free electrons and photons in the medium through which they pass. The energy of an electron is too great to be absorbed directly by the medium. The electron in turn ejects other so-called secondary electrons, and so on, until the energy of the last electron ejected is of the same order of magnitude as that of the covalent bonds.

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