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In this paper we report on the optical and scintillation properties of Cs2LiYCl6 : Ce3+ and Cs2LiYCl6 : Pr3+ crystals. Crystals of Cs2LiYCl6 doped with different Ce and Pr3+ concentrations were grown and studied under optical, X-ray, gamma ray, and thermal neutron excitation. These scintillators exhibit core-valence and self-trapped exciton luminescence in addition to fast emission from Ce3+ and Pr3+ Efficient thermal neutron detection was observed for both scintillators. The position of the neutron peak in the pulse height spectra was found at about 5 times the channel number of the position of the 137Cs 662 keV gamma peak. [ABSTRACT FROM AUTHOR]

In this communication, we investigate the scintillation properties of LaBr3 :Ce as a function of Ce concentration. We have studied crystals nominally doped with 0.5%, 5%, 10%, 20%, and 30% Ce (by mole). Previous reports suggest that as the Ce content increases, there is a decrease in light output and little or no change in decay time constants. These results show that the light output does not change with Ce concentration up to 30% and depends mostly on the crystal quality. On the other hand we have found the timing properties to be a strong function of Ce concentration. As the Ce content increases, the principal decay time constant of scintillation decreases from 26 ns for 0.5%Ce to 17 ns for crystals with > 5% Ce. Moreover, there is a significant change in rise time constants. The rise time measured for a sample doped with 0.5% Ce is up to 9 ns, whereas for samples doped with > 10% Ce it is less than 0.5 ns. The change of rise time has a major effect on the timing properties of this scintillator, with timing resolution improving from 361 Ps to less than 100 PS (full width at half maximum). [ABSTRACT FROM AUTHOR]