Growth and spectroscopic characterization of Pb2+:CaF2 crystals I. Nicoara, M. Paraschiva, M. Stef and F. Stef Eur. Phys. J. B, 85 8 (2012) 292 Published online: 29 August 2012 DOI: 10.1140/epjb/e2012-30433-3