Ce3+ 5d-centroid shift and vacuum referred 4f-electron binding energies of all lanthanide impurities in 150 different compounds

Scintillation properties of LuAG:Pr grown by Furukawa Co. Ltd., Japan, have been studied. The best crystals display light outputs up to 19000 ph/MeV and an energy resolution of 4.6% at 662 keV. The scintillation yield is found to be a function of size and temperature of the sample; it can be enhanced by 40% upon heating to 450 K. Radioluminescence spectra show both d- f and f-f transitions of Pr3+ ions; the contribution of the latter increases with temperature. The scintillation decays are complex, with a fast decay constant of 20 ns. The presence of 176Lu induces high background activity.

Scintillation Properties of Praseodymium Activated ${\rm Lu}_{3}{\rm Al}_{5}{\rm O} _{12}$ Single Crystals

Vacuum-Ultraviolet Photon Detections.

A2MgTeO6 (A = Ba, Sr, Ca) ceramics were prepared by solid-state route and their microstructure and microwave dielectric properties, as well as the vibrational phonon modes were investigated using the resonance method and spectroscopic techniques for the first time. For the optimized sintering temperatures, Ba2MgTeO6, Sr2MgTeO6, Ca2MgTeO6 materials presented the following properties: er of 11, 14.3, and 13.2; Quxf of 25, 27.5, and 81 THz, and τf of −16, −61, and −81 ppm/°C, respectively. XRD besides Raman and infrared spectroscopies were employed to investigate the structures of these materials and the results showed that Ba- and Sr-based double perovskites belong to the tetragonal I4/m space group, while Ca-based materials exhibit a monoclinic P21/n structure. The phonon modes were evaluated and the intrinsic microwave dielectric properties were discussed in terms of the A-site substitution on tellurium-based ceramics. The number of bands observed in both spectroscopic techniques agrees well with the grou...

Vibrational Studies and Microwave Dielectric Properties of A-Site-Substituted Tellurium-Based Double Perovskites

The vacuum referred binding energy (VRBE) of the single electron in the lowest energy 3d level of Sc2 +, V4 +, Cr5 +, the lowest 4d level of Y2 +, Zr3 +, Nb4 +, Mo5 + and the lowest 5d level of Ta4 +, and W5 + in various compounds are determined by means of the chemical shift model. They will be compared with the VRBE in the already established lowest 3d level of Ti3 + and the lowest 5d level of Eu2 + and Ce3 +. Clear trends with changing charge of the transition metal (TM) cation and with changing principle quantum number n = 3, 4, or 5 of the nd level will be identified. This work will demonstrate that the trends correlate with the VRBE in the free ion nd TM cation level. The acquired knowledge on the VRBE of the electron in the nd TM impurity levels but also on TM based compounds with nd type of conduction band bottom provides new insight in the luminescence properties of TM activated compounds.

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Jean-Luc Lefaucheur

Papers

Scintillation properties of selected oxide monocrystals activated with Ce and Pr

VUV spectroscopy and low temperature thermoluminescence of LSO:Ce and YSO:Ce