Study of optical and dosimetric properties of doped fluoride crystals

Optical properties and radiation effects of various fluoride crystals and t heir possible application to solid state dosimetry were studied. In particu lar optical absorption, FL, OSL, TL and OSTL of LiKYF5 and LiKYF5:Pr3+ crys tals were measured and compared to those of pure and Eu3+-doped LIF. After X- or beta -irradiation of LiKYF5:Pr3+ a strong TL was recorded, in samples irradiated at RT also an OSTL could be stimulated at LNT; the stimulation maximum for the OSTL was at 442 nm. The traps responsible for the TL were s table to about 600 K. In LiF:Eu3+ the TL could also be excited by VUV radia tion. The VUV excited TL had excitation maxima near 125 and 190 nm. An OSTL emission was recorded in pure irradiated LiF crystals; and had an excitati on maximum at 190 nm, indicating that the TL in the doped samples and the O STL in the pure crystals are due to the same trapping states. Prolonged ill umination into the F-band caused in LiF a decrease of the M-luminescence an d an increase of the R+-emission, which is apparently due to an M to R conv ersion. The dose dependence of the TL in LiKYF5:Pr3+ was found to be linear for beta doses to above 2 kGy. The TL sensitivity of the powdered LiF:Eu3 samples was an order of magnitude greater than that of pure LiF crystals, but by an order of magnitude lower than that of the known efficient LiF:Mg Ti (TLD-100) phosphor. The sensitivity of LiKYF5:Pr3+ crystals were of the order of the TLD-100 phosphor. (C) 2001 Elsevier Science B.V. All rights re served.