Effect of lithium co-dopant on the thermoluminescence response of some phosphors
The effect of lithium co-dopant on the thermoluminescence of some TL phosphors has been studied. These results show that lithium co-dopant when present in CaSO4:Dy, CaSO4,Tm, CaF2:Mn, MgB4O7:Dy, MgB4O7:Tm, MgB4O7:Tb, MgB4O7:Mn, CaB4O7:Dy and CaB4O7:Tm thermoluminescent phosphors induces higher luminescence efficiency either due to better incorporation of activator ions or due to improvement in energy transfer processes. Go-doping with Li of the above given phosphors resulted in increasing the TL sensitivity from 1.2 to 3.4 times, when compared with that of the TL phosphors without lithium co-dopant. The effect of co-doping with lithium impurities on the thermoluminescence of various TL phosphors is also studied in dependence of Li concentration, of the chemical form of added lithium compounds and of the method of addition of Li co-dopant during the TL phosphor preparation. It is observed that the addition; of Li co-dopant induces in some TL phosphors enhancement of the lower temperatur...e peak which is correlated with the increase of TL sensitivity. The high TL output of these TL phosphors could be used in dosimetric practice for special short-term measurements. (C) 2000 Elsevier Science Ltd. All rights reserved.