CaI2 and CaI2(Eu) Scintillation Crystals

Scintillation crystals of CaI2 and CaI2(Eu) have been produced which iypically show pulse heights of 180% relative to NaI(Tl). The emission spectra for both pure and activated materials are well matched to a S-ll phototube response. Pure CaI2 has a decay time of 0.55, ?sec; CaI2(Eu) has a 0.79, ?sec decay time. Though this material is difficult to grow and to package, performance results thus far obtained are encouraging.