Geiger Muller Counter is named after its developers: Geiger and Muller. It is a metal cylinder filled with low-pressure gas sealed with a plastic or ceramic window at one end. This counter works in Geiger region with two specialities.
The gas multiplication factor is so large that an avalanche dies in at one point but spreads all over the entire length of the central wire.
Large output pulses are obtained as the output pulse is independent both of the energy and nature of the particles detected.
The ionizing particle passing through the tube ionizes the gas and electrons so produced move towards Anode. The velocity is quite high and they later produce secondary electrons after repeated collisions with the particles of the gas. These secondary electrons further produce more electrons in Geometric progression.
Due to this large multiplication action, a large ionization current is produced.
It can count alpha, beta, gamma particles as well as cosmic rays.
It has high sensitivity.
Power supply need not be precisely regulated as the pulse height is constant over a large range.
Because of the fact that output pulse is very high, so the Amplification needed is also very subtle.
Energies cannot be measured by it as it has a lack of differentiating abilities.
It cannot detect uncharged particles like Neutrons.
It is less efficient due to the large paralysis time limits and large dead time.
Quenching agent used in this counter often decomposes, leading to less lifetime of the GM Counter.
Thus, GM Counter is the one which is primarily used due to its advantages. Although it is not free from disadvantages, still its uses make it preferable over other counters.