The Geiger Muller Tube
The Geiger – Muller tube can be used to detect ionising radiation and count the number of ionising particles. When gas enters the chamber of either instrument through a window at one end it ionises the molecules of a gas at low pressure. A voltage applied across the tube causes the ions to accelerate towards the anode/cathode and an electrical pulse passes through the circuit. If a steady current is produced this indicates the intensity of radiation.