Page 212 - Radiation Safety

Particulate : Alpha

• Helium nucleus: 2 protons and 2 neutrons tightly bound together

• Emitted from naturally occurring radio nuclides such as uranium and
thorium

• Lose energy by collisions with atomic electrons - cause ionizations to
occur

• Directly ionizing particles - cause ionization of an atom without any
intermediate interaction taking place

• Cause large specific ionization (number of ion pairs formed per unit
energy) because of their double positive charge and large mass

• Lose their energy in short distance hence range in media is short (less of
external hazard but present an internal hazard)

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