Thermoluminescence in Sodium Silicate by uv Excitation

Thermoluminescence (TL) in sodium silicate, known to be excitable by x rays and gamma irradiation, was found to be excited by uv light. Only the glow peak appearing below room temperature (RT) is excitable whereas additional peaks that had been found above RT after γ irradiation do not appear. This fact indicates that γ rays may create new defects while uv light can only excite existing imperfections. The observed peak at about 130°K is found to consist of many overlapping components corresponding to a continuum of activation energies between 0.16 and 0.38 eV. The emission, which was found to be in the visible, peaked at ∼500 mμ. The dependence of TL intensity on the uv excitation dose and the decay of phosphorescence were also studied.