The detection and photopeak efficiences of a NaI cylindrical crystal, 7.62 cm diam and 7.62 cm high, containing a 0.63 cm diam well, 4.13 cm deep, were experimentally determined for 0.51 MeV gamma radiation from 11C positron annihilation. The pulse-height distribution measured with the source on top of the crystal was used with probability theory to obtain an approximate synthetic summed spectrum for the source in the well. This in turn was used to analyze the observed pulse-height distribution for the source in the well. The detection and photopeak efficiencies are 0.70±0.02 and 0.49±0.01, respectively, from which the photofraction is 0.70±0.03. Agreement with calculated values is good.
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.