Ionization of air
(or other gases)

Direct measurement of exposure or exposure rates, with minimal energy dependence.

Ionization of gas with
multiplication of
electrons in detector

Detection of individual events, i.e. alpha or beta particles & secondary electrons, for measuring activity (in samples or on surfaces) & detecting low intensities of ambient x or gamma radiation; precautions required due to energy dependence.

Ionization of
semiconductor

Detection & energy measurement of photons or particles; primarily for laboratory use.

Ionization & excitation
followed by light emission

Detection of individual events;

- NaI (Tl) - photons; energy spectrometry

- ZnS (Ag) - alpha particles; detection only

- Detection of low-energy beta emitters mixed with the scintillation fluid.

Ionization of Ag Br

Personal exposure monitoring.

Excitation of crystal;
light release by heating

Personal and environmental exposure monitoring.