Wiktionary
n. (context physics English) A detector of particles and ionizing radiation which uses a photomultiplier to generate flashes of light
WordNet
n. counter tube in which light flashes when exposed to ionizing radiation
Wikipedia
A scintillation counter is an instrument for detecting and measuring ionizing radiation by using the excitation effect of incident radiation on a scintillator material, and detecting the resultant light pulses.
It consists of a scintillator which generates photons in response to incident radiation, a sensitive photomultiplier tube which converts the light to an electrical signal and electronics to process this signal.
Scintillation counters are widely used in radiation protection, assay of radioactive materials and physics research because they can be made inexpensively yet with good quantum efficiency, and can measure both the intensity and the energy of incident radiation.
Usage examples of "scintillation counter".
The bored secretary broke off updating her desk diary to pick it up and thrust it under the makeshift scintillation counter that Nigel Frogland had set up in the office the previous afternoon: when it began to buzz her jaw dropped and she nearly spilt her coffee.
What he really needed was a high-grade scintillation counter, but that was nothing anyone could carry in a pocket.
The device contained no fissionables it wouldn't have been detected by any kind of a scintillation counter, only the kind of X ray or muon scanner that no one would put a valuable bird through.