Main Entry: pho·to·mul·ti·pli·er tube

Pronunciation: \ˌfōt-ō-ˈməl-tə-ˌplī(-ə)r-\

Function: noun

: a vacuum tube that detects light especially from dim sources through the use of photoemission and successive instances of secondary emission to produce enough electrons to generate a useful current—called also photomultiplier