14 MeV neutron activation of ternary copper silver selenide gives rise to a predominant activity from the 0.511 MeV annihilation peak from the three elements when -ray spectrometry is used. To overcome the interference problems, X-ray spectrometry was applied to the simultaneous nondestructive determination of silver and selenium, after which copper can be determined by
-ray spectrometry. The results of analysis show a relative error not higher than ±5%, when the samples were diluted with H3BO3 /
90%/ to minimize the interelement effects.