A COMPARATIVE-ANALYSIS OF 3 THERMOLUMINESCENT PHOSPHORS LIF-MG,TI (TLD-100), LIF-MG,CU AND LIF-MG,CU,P

Three LiF based thermoluminescent (TL) phosphors, namely, LiF:Mg,Ti, L iF:Mg,Cu and LiF:Mg,Cu,P were investigated for their TL glow curves, T L sensitisation, TL supralinearity, phototransferred TL (PTTL), residu al TL (RTL) and emission spectra. Contrary to recently reported result s, LiF:Mg,Cu,P did not show any sensitisation in the dose range 0.5-10 0 kGy. In fact, both LiF:Mg,Cu and LiF:Mg,Cu,P show significant loss o f TL sensitivity with increase in dose. All the three phosphors show t he presence of PTTL. PTTL in LiF:Mg,Cu and LiF:Mg,Cu,P at their respec tive saturation doses are 2 and 3 orders of magnitude smaller than LiF :Mg,Ti. From the analysis, supralinearity and sensitisation appear to be related phenomena, while PTTL seems to be unrelated. On the other h and, there appears to be correlation between PTTL and RTL. All the thr ee phosphors show existence of 10 peaks. with close resemblance in the ir peak positions. The trapping centres or the peaks could be attribut ed to Mg related defect complexes in the LIF lattice.