Thermoluminescent dosimeter Li2B4O7:Mn,Si – a false-dose problem

The false-dose effects are investigated in the thermoluminescent detectors of ionizing radiation based on Li2B4O7:Mn,Si. To reveal the mechanism of daylight sensitivity, thermo- luminescence, EPR, and luminescence excitation studies and technological experiments were undertaken. A 400 nm light was shown to be most effective to store the dose and to excite the luminescence band near 600 nm. A charge-transfer complex of a casual titanium impurity is supposed to be responsible for daylight false-dose storage. Another mechanism of a false-dose storage is supposed to be caused by a thermally induced stress, which yields a high-temperature thermoluminescence of Li2B4O7:Mn,Si detectors. Increasing the temperature of the sintering of tablets eliminates both false-dose effects. Possible models of energy storage are discussed.