Single Crystal Growth and Luminescence Properties of CeF $_{3}$ -CaF $_{2}$ Solid Solution Grown by th

(Ce_xCa_1-x)F_2+x single crystal with x = 0.0001 - 0.03 were grown by the mu-PD method. Ce³⁺ doping in CaF₂ lattice gives rise to characteristic absorption and emission bands, which are governed by the characteristics of the isolated Ce³⁺-F_i ^- C_4v pair centers and small clusters composed from these pairs. With increasing Ce concentration there is a strong increase of the absorption bands related to the cluster centres, but the radioluminescence spectra are always governed by the emission of the isolated Ce³⁺-F_i ^- C_4v pairs without noticeable changes in the emission band shape. Highest radioluminescence intensity is achieved for Ce 0.1{%} concentration and above 1{%} of Ce the onset of concentration quenching is observed. Scintillation response is governed by the energy transfer from the CaF₂ host lattice and even for the Ce3{%} sample the dominant scintillation decay time is about 50{%} longer with respect to the photoluminescence decay time of Ce³⁺-F_i ^- C_4v pair centres. Energy transfer processes and the role of different Ce³⁺-based centers are discussed.