1. Gas detectors

The passage of a charged particle through a gas produces ionization and excitation of the gas molecules along its path. If an electric field prevails in the gas volume, the migration of the ion-electron pairs produced towards the electrodes will induce an electrical signal indicating the interaction of the particle in the gas. The main gas counters used are ionization chambers, proportional counters, Geiger-Müller counters and multi-wire proportional chambers, which have undergone vertiginous development since the 1970s.