Single Crystal Growth and Luminescence Properties of CeF $_{3}$-CaF$_{2}$ Solid Solution Grown by the Micro-Pulling-Down Method

(Ce
_x
Ca
_1-x
)F
_2+x
single crystal with x = 0.0001 - 0.03 were grown by the mu-PD method. Ce
³⁺
doping in CaF
₂
lattice gives rise to characteristic absorption and emission bands, which are governed by the characteristics of the isolated Ce
³⁺
-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 Ce
³⁺
-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 CaF
₂
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 Ce
³⁺
-F
_i

^-
C
_4v
pair centres. Energy transfer processes and the role of different Ce
³⁺
-based centers are discussed.