In the scintillation spectrometer described, the main detecting crystal of NaI(Tl) is enveloped by a hollow cylinder of NaI(Tl) in anticoincidence with the main crystal. This system completely suppresses the peaks associated with the escape of the two quanta from the annihilation following pair production, and it reduces the Compton background by a factor of 7 for 4.43-Mev gamma rays and by a factor of 5 for those of 6.1 Mev.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.