Luminescence of LiKYF5:Pr3+ crystals

Abstract

Abstract X-luminescence (XL), photoluminescence (PL), optically stimulated luminescence (OSL), thermoluminescence (TL), phototransferred thermoluminescence (PTTL) as well as optical absorption have been studied in pure and Pr3+ doped LiKYF5 crystals. Dependencies of the luminescence efficiency on the Pr3+ concentration and on the radiation dose have been measured and possible applications of the novel TL phosphor based on LiKYF5 : Pr3+ for solid state dosimetry have been investigated. There are main emission bands at 340 and 385 nm in the XL and the PL spectra of pure crystals and both these PL emission bands have an excitation maximum at 215 nm. Additional narrow emission bands at 230, 270, 479, 530 and 605 nm are observed from the LiKYF5:Pr3+ crystals. In the doped crystals, the 215 nm light mainly excites the 230 and the 270 nm emission, and there are additional excitation maxima at 442, 459, 468 and 480 nm. During heating of X- or β-irradiated crystals, TL peaks have been recorded and thermal activation energies have been evaluated by various methods. TL from the LiKYF5: Pr3+ crystals shows emission bands at 229, 262, 340, 486, 527, 610, 640 and 705 nm whereas there are only a main 340 nm band and weaker bands at 486 and 450 nm on the TL spectra of the pure crystals. Samples exposed to prolonged X- or β -irradiation at RT and then illuminated with the 295 or 442 nm light at LNT show strong PTTL during heating from LNT to RT. The dose dependence of the TL intensities in LiKYF5: Pr3+ has been found to be linear for radiation doses up to 2 kGy.