scintillator

noun
scin·​til·​la·​tor | \ ˈsint-ᵊl-ˌāt-ər How to pronounce scintillator (audio) \

Medical Definition of scintillator

1 : a phosphor in which scintillations occur (as in a scintillation counter)
2 : a device for sending out scintillations of light