The ions produce an electric current, which is the signal output of the detector.
The ions produced correspond to the gas type used.
Every nitrate ion reduced to ammonia produces one OH ion.
Each individual ion produces many point defects in the target crystal on impact such as vacancies and interstitials.
Atoms and monatomic ions produce colors by excitation and decay of electrons in their atomic orbitals.
The gas becomes electrically charged and the ions produce an electric current, which is the signal output of the detector.
The process of track production is essentially the same by which swift heavy ions produce ion tracks.
Finally he decided that ions, hitting the upper air along the terminator, produced secondaries and cascades which descended everywhere.
Also, those excited ions aligned with the signal field produce more stimulated emission.
Naturally the different ions produce different effects.