ABSTRACT
This chapter looks at the physics of radiation, radioactivity and radioactive decay. It discusses the health effects from ionising and non-ionising radiation together with an outline of how to monitor for radiation. Beta decay occurs when a nucleus decays with the emission of an electron or beta particle. It is important to realise that the electrons that are lost in this process are not those from the orbit of the nucleus. Gamma decay occurs where a nucleus is in an excited state and it moves into a lower energy state, emitting energy or a photon. Charged particles such as alpha and beta rays and protons cause ionisation of tissues due to their electrical force. The Geiger counter consists of a cylindrical tube that is filled with gas. Dosimeters are able to provide an accurate measure of absorbed dose. Non-ionising or electromagnetic radiation is essentially energy waves that are composed of electric and magnetic field components.
