Scintillation characteristics of nonstoichiometric phases formed in MF 2–GdF 3–CeF 3 systems Part III. Dense Gd 1− x− yM xCe yF 3− x tysonite-related crystals (M=Ca, Sr)

Abstract

We evaluated the scintillation characteristics and the radiation hardness of Gd 1− x Ca x F 3− x and Gd 1− x Sr x F 3− x tysonite-type solid solutions (close to 6.6 g/cm 3 in density) doped with Ce which were grown from the congruent melt. As the Ce concentration increased, the Ce 3+ emission at 345 nm increased to a level comparable with the Gd 3+ emission at 310 nm. Both emissions, however, were slow with the decay constant in the order of ms. The radiation hardness, which was roughly 10 4 rad, tends to degrade as the wavelength decreases and/or the Ce concentration increases. Both spontaneous recovery and UV annealing of the radiation damages were significant. The intensity of the γ-ray excited luminescence, integrated over time, was as large as 50% of that in BaF 2 (12% of that in CdWO 4). When the Ce concentration is nil or only small, the yellow–green luminescence for UV excitation was as intense as in CdWO 4. Although the present crystals are not good for the applications in high-energy physics experiments, they may find applications in display devices, thermal neutron monitors, etc.