Thermoluminescence characterization of Ag-doped Li2B4O7 single crystal materials

摘要

In this study, the thermoluminescence (TL) characteristics of Ag-doped and undoped lithium tetraborate (Li2B4O7, LTB) materials, grown using the Czochralski method, were reported. The TL properties of LTB:Ag, such as glow curve structure, dose response, fading and reproducibility, were investigated. The glow curve of the Li2B4O7:Ag single crystal consists of four peaks located at approximately 75, 130, 190 and 275 degrees C; in undoped LTB, the single crystal shows a broad glow curve with peaks at 65, 90, 125, 160 and 190 degrees C using a heating rate of 5 degrees C/s in the 50-350 degrees C temperature region. The high temperature peak of Ag-doped sample at 275 degrees C has a nonlinear dose response within the range from 33mGy to 9Gy. There is a linear response in the range of 33-800mGy; after which, a sublinear region appears up to 9Gy for Ag-doped LTB single crystal. For undoped single crystal, the dose response is supralinear for low doses and linear for the region between 1 and 9Gy. The thermal fading ratio of the undoped material is almost 60% for the high temperature peak after 7days. Ag-doped LTB single crystal exhibits different behaviour over a period of 7days.