What instrument is used to detect radioactive matter?
Dosimeters detect and measure the cumulative ionizing radiation
they see over time. Geiger counters detect the real-time flux of
ionizing radiation at a specific location, and scintillators detect
individual, real-time ionizing events and usually are constructed
in a way to quantify variations in the ionizing energy.
Usually, dosimeters are placed on or near an at-risk individual
for a length of time to measure their total exposure, while Geiger
counters are used by rad-techs to determine how safe an experiment
is or if a dangerous event is occurring. Scintillators are used
almost exclusively by experimentalists to collect and sort data at
high resolution.