Optically stimulated luminescence of LiF:Mg,Cu,P with different dopant concentrations

Abstract

A study of the optically stimulated luminescence (OSL) properties of LiF:Mg,Cu,P material has been performed with respect to the dopant concentrations in the following ranges: Mg (0.1–1.0 mol%), Cu (0.005–0.5 mol%), P (0.15–5.0 mol%). Over 40 differently doped LiF:Mg,Cu,P batches were successfully investigated for their OSL signal. Parameters describing the shape of the OSL decay curves after continuous (CW-OSL) and linear stimulation modes (LM-OSL), including the optimum annealing conditions have been evaluated. The results show that the OSL signal of the LiF:Mg,Cu,P is associated with the TL peak 1 and TL peak 2. Moreover, it was found that the OSL decay curve is composed of fast and slow components. The optimal concentration of the Mg, Cu, P activators for OSL were found to be in the following ranges: Mg (0.2–0.6 mol%), Cu (0.001–0.05 mol%), P (0.6–1.25 mol%). Another important finding was the fact that LiF:Mg,Cu,P requires different annealing conditions for OSL than for TL. The optimal annealing procedure for OSL was found to be: 240 °C/10 min followed by 190 °C/10 min. For this procedure the OSL sensitivity is increased by approximately 60% compared to the initial signal after standard annealing at 240 °C/10 min. LiF:Mg,Cu,P OSL signal shows high fading, reaching nearly 40% loss of the signal within 2 h storage time in the dark and at room temperature. The dose response of OSL signal was confirmed to be sublinear, similarly as in case of TL.