Optically stimulated luminescence of the [20% Li₂CO₃ + x% K₂CO₃ + (80 - x)% B₂O₃] glass system

Highlights: • Varying composition of borate glasses by adding lithium carbonate and potassium carbonate introduces different CW-OSL decay patterns. • Depending on the parameter chosen to normalize the dose-response curve, the sensitivity range changes. • The decay curves of the OSL signal change when a heating step precedes the readout. - Abstract: This study analyzed the optically simulated luminescence (OSL) of borate glasses containing lithium carbonate and potassium carbonate. Borate glasses present desirable characteristics for dosimetry and have been extensively analyzed in relation to thermoluminescence (TL). Five formulations containing 20% of Li₂CO₃ and different amounts of B₂O₃ and K₂CO₃ were produced. Their OSL signal was analyzed following exposure to beta particles. The decay pattern typical of continuous wave stimulation (CW-OSL) was observed for all compositions. Depending on the parameter chosen to normalize the dose-response curve, the sensitivity range changed. If the initial OSL intensity was chosen as reference, the composition containing 65% B₂O₃ and 15% K₂CO₃ (named L15KB) presented the most intense signal. However, if the total area below the curve was considered, the composition containing 70% B₂O₃ and 10% K₂CO₃ (named L10KB) was the most sensitive. A comparison of the OSL decay for the two quoted compositions, after pre-heating to 200 °C for 10 s prior to the OSL readout, showed a slight change in the decay pattern compared to the absence of pre-heating. The pre-heating treatments also showed the correlation between the shallow traps and the fast component of the OSL decay for L15KB. For all compositions, an increase in dose implied an increase in emitted signal, and no saturation was observed between 0.1 Gy and 7 Gy.