- Scintillation counters use the fact that some substances produce a flash of light when struck by ionising radiation

o When some substances are irradiated with alpha, beta or gamma rays, they emit a flash of light

o Photomultiplier tubes convert the light to electrical signalso Used in radiation protection, measuring the intensity and energy of incident

radiation - Electrons in there substances are excited by the radiation and emit photons of light when

the electrons return to lower energy states- Flashes of light are counted electronically to measure the amount of radiation