Some studies of thermoluminescent MgF2 phosphors

Optical grade MgF2, fused in nitrogen atmosphere with individual dopants Mn, Dy, Tm and Tb (0.1% by wt), has been studied. After γ-ray irradiations phosphors exhibit 10 TL glow peaks between RT and 4000C around 80, 115, 137, 165, 190, 225, 265, 290, 315 and 3600C. Their response to u.v. and γ-rays, their PTTL, TL emission spectra, photoluminescence spectra and absorption spectra are reported. Rare earth ions in a triply ionized state replace Mg2+ in MgF2 and take part in TL emission, whereas Mn is in a doubly ionized state in the doped phosphor. High temperature treatment in air enhances the high temperature peaks in MgF2:Tb, while the contribution from lower temperature peaks becomes negligible. MgF2 phosphors show γ-induced sensitization. For a post-annealing for 1 h at 3000C and a test exposure of 10 R at RT, the sensitization factor is 2.2 for MgF2:Mn (pre-exposed to 103R) and 25 for MgF2:Tb (pre-exposed to 5 x 104R). (author)