The scintillation intensity and decay from Nd3+4f25d and 4f3excited states in several fluoride crystals

Nd 3+ -doped LaF 3 , LiYF 4 , CsY 2 F 7 , BaY 2 F 8 and BaF 2 crystals were investigated. For scintillator applications, the characteristics of the fast Nd 3+ 4f 2 5d to 4f 3 emission component is of interest. The effective 4f 2 5d to 4f 3 scintillation decay time under gamma irradiation was found to vary from 5 to 42 ns, depending on the host lattice. Light yields were determined under X-ray excitation. The 4f 2 5d to 4f 3 output from many samples was seriously affected by impurity absorptions. After correcting for these, an estimate was made of the maximum possible 4f 2 5d to 4f 3 light yield to be expected in very pure Nd 3+ -doped crystals. In neither of the cases was a 4f 2 5d to 4f 3 light yield of more than about 1000 photons per MeV of X-ray energy found. In addition to Nd 3+ 4f 2 5d to 4f 3 emission, Nd 3+ 4f 3 to 4f 3 and host emissions were also recorded at wavelengths shorter than 550 nm. A semi-quantitative model is given for the Nd 3+ 4f 2 5d to 4f 3 , 4f 3 to 4f 3 and host emission intensities.