Impact of preparing temperature and soaking time on OSL of NaLi2PO4:Eu phosphor

Abstract

NaLi₂PO₄:Eu was an optically stimulated luminescence (OSL) phosphor with good OSL stability but low OSL sensitivity. Many studies have indicated that the OSL properties of phosphors can be affected by modifications during the preparation process. The main focus of this research is to improve the NaLi₂PO₄:Eu OSL sensitivity by investigating the effects of the preparing temperature and soaking time on thermoluminescence (TL) and OSL properties. The samples synthesized at different preparation temperature and soaking time all exhibit pure phases. Differential Scanning Calorimetry indicates that the material undergoes an endothermic process between 850 °C and 1000 °C, and after 1000 °C, the material experiences an exothermic crystallization process. Our research find that the TL main peak and the initial OSL count are influenced by the preparing temperature in the material synthesis process, however, the stability of TL and OSL is not affected by the preparing temperature. Shortening the soaking time can increase the OSL stability of this material. Our measurement results suggest that the TL and OSL signals may originate from different traps. The process of heating at 1000 °C for 2 h has good OSL sensitivity and stability (3 % of fading). It has a linear dose response in the range of 0.1–5 Gy. Furthermore, the repeatability of this phosphor is excellent.