Luminescence mechanism and energy transfer in doubly-doped BaY₂F₈:Tm,Nd VUV scintillator

Doubly-doped BaY₂F₈:Tm,Nd scintillation crystals were grown by modified micro-pulling-down method. Nd co-doping was chosen to enhance the energy transfer from the host lattice to the Nd³⁺ luminescence center via the 5d-levels of Tm³⁺, due to the overlap of Tm³⁺ 5d-4f emission spectrum with the Nd³⁺ 4f-5d absorption. The energy transfer was clearly evidenced in the BaY₂F₈:Tm,Nd. This process is not complicated by an energy migration to killer centers and/or cross-relaxation. The radioluminescence process is complicated by an energy transfer from the host lattice exciton states to the lower f-levels of Tm³⁺ ion.