détecteur à section de capture

OBS: A type of ionization detector that responds to the permanent gases. It consists of a small ionization chamber in which the carrier gas and solute are irradiated with electron from a β-ray emitter while a potential is applied across the cell. When solutes enter the chamber there is a current change arising from the change in total cross-section for ionization.
OBS: The carrier gas most commonly used is hydrogen but nitrogen and helium are also employed.