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The scintillation and luminescence properties of SrI 2 :1% Sm 2+ and SrI 2 :1% Er 3+ are reported. Single crystals were grown by the vertical Bridgman technique. Broad band Sm 2+ 5d–4f emission was observed centered at 750 nm with a radiative lifetime of 1.25 µs. The photoluminescence decay time increases with temperature due to self-absorption. With Er 3+ a clear charge transfer band was identified at 295 nm. The spectroscopic properties of Sm 2+ and Er 3+ are compared with those of Eu 2+ , Yb 2+ , Ce 3+ , and Nd 3+ doped in SrI 2 . The results are combined to construct a diagram with the vacuum referred electron binding energies for all divalent and trivalent lanthanide ions in SrI 2 which is fully consistent with the spectroscopic observations. [ABSTRACT FROM AUTHOR]

Energy transfer from donor Gd 3+ to acceptor Ce 3+ ions was studied in low doped lutetium aluminum garnet, LuAG:Ce,Gd. High purity single crystalline films were prepared by liquid phase epitaxy. The mechanism of nonradiative energy transfer from 6 P J (Gd 3+ ) multiplet to crystal field split 5d 2 ( 2 D) states of Ce 3+ was established as long-range dipole–dipole interaction and the average critical transfer distance between Gd 3+ and Ce 3+ ions was found ~14 Å at room temperature. It is shown that the single step energy transfer between donor–acceptor pairs is dominant while migration of excitation energy within the donor Gd 3+ subsystem is only a small perturbation in the energy transfer mechanism in the studied low doped garnets. [ABSTRACT FROM AUTHOR]

Gd 3+ -doped borosilicate glasses are prepared in different melting atmosphere. Absorption spectra, decay time, luminescence spectra under UV and X-ray excitation are investigated. With melting atmosphere changing from air to CO, the luminescence intensities of Gd 3+ at 313 nm under the excitation of UV and X-ray are both enhanced. This mainly results from the reduction of Gd 3+ , which is validated by electron paramagnetic resonance (EPR). The optimal Gd 2 O 3 content for the glasses prepared under CO atmosphere is 7.5 mol%, whose integral scintillation efficiency is 20% compared with Bi 4 Ge 3 O 12 . [ABSTRACT FROM AUTHOR]