“…(Weber and Bierig 1964). There has been a large number of research papers on the luminescence of natural fluorite measured by the steady-state method (Illiev et al 1988;Aierken et al 2000Aierken et al , 2003Bodył 2006;Petit et al 2007;Czaja et al 2008;Bodył 2009) or the time-resolved method (Gaft et al 1998(Gaft et al , 2001a(Gaft et al , b, 2005(Gaft et al , 2008. Moreover, the synthetic CaF 2 , BaF 2 and SrF 2 crystals doped with RE ions were investigated intensively (Wood and Kaiser 1962;Kirilyuk 1973;Fenn et al 1973;Tallant and Wright 1975;Seelbinder and Wright 1979;Chrysochoos et al 1982Chrysochoos et al , 1983Illiev et al 1988;Caldino et al 1989;Oskam et al 2002).…”