The amount of each pulse of light represents a measure of the energy deposited in the scintillator. The ability to measure this energy means that radiation from various sources can be identified and at the same time one can evaluate the magnitude of the source. Determining the type of gamma rays allow us to infer the type of radionuclide that emitted them. Geiger counters can be made as small hand held instruments. They are easy to use as portable radiation monitors.
Scintillation counters are generally large laboratory instruments.
Detecting alpha particles is technically more difficult than detecting beta particles and gamma rays. Like beta and gamma radiation, alpha particles can produce ionizations, but they are not as penetrating. In principle, alpha particles could be detected with an ordinary GM tube. However, alpha particles are best measured by what are called gas flow proportional counters. In some proportional counters, the radioactive source that is to be measured, or the sample, is placed directly inside the detector.