(1)  A radiation source is a thing that emits or may emit radiation.

(2)  A radiation source can be radioactive material or a radiation apparatus.

(3)  Radioactive material is material that spontaneously emits ionising radiation as a consequence of nuclear transformations.

(4)  A radiation apparatus is an apparatus that –

(a) produces radiation when energised; or

(b) is, if assembled or repaired, capable of producing radiation when energised.