Analysis of TL glow curves based on the model of two emission centers

The technique of three-dimensional thermoluminescence (3D-TL) spectrum can separate a different detrapping process occurring in a material through the temperature resolution, whereas it can separate a different recombination process, which occurs simultaneously in the material, through the wavelength resolution. In this paper, the algorithm of numerical analysis based on the model of two recombination centers is newly developed and applied to the 3D-TL emitted from a MgAl2O4 spinel crystal exposed to UV light. The 3D-TL spectrum of a MgAl2O4 crystal exposed to UV light for 600 sec at room temperature has 710 nm peak at 472 K (TL-1) and 520 nm peak at 490 K (TL-2). The emission center for TL-1 is associated with the hole captured at Cr2+ site and TL-2 is the hole at V2+ site. The thermal behavior of the electrons from the single trap can be described by TL-3 being sum of TL-1 and TL-2. The TL glow curve of the MgAl2O4 crystal was analyzed with the new algorithm. The trap depth results in 0.61 eV and is markedly different from a value of 0.66 eV determined by the conventional model. The recombination rates were concluded to be γ1h10 = 0.33 s-1 and γ2h20 0.044 s-1. (S.Y.)