MCP-100, MYS-N, MTS-7, MTS-100, and MCP-N standard thermoluminescence detector materials are annealed and irradiated. Glow curves and all trap parameters are determined. For these materials new theoretical energy band models are suggested and differential equations governing the charge carrier traffics are derived. The equations are solved by using computer-based numerical methods. During the simulations, experimental data measured in the previous step are given to computer code as the initial conditions. Experimental and numerical results show that the electron-band structures of standard thermoluminescence crystals are represented fairly well by the suggested models.
a b s t r a c tIn this study, the fading mechanism of Seydis -ehir alumina in Turkey, which is considered to be used for radiation dosimetric purposes, was investigated. The materials were first exposed to beta radiation and then stored in dark and dry ambient conditions at room temperature (RT) at previously desired storage periods. It was observed that the glow curve of Seydis -ehir alumina consists of four glow peaks between RT and 400 1C. The glow peaks (peaks 1, 2 and 3) between room temperature and 250 1C possessed very high levels of anomalous fading. However, the intensity of new glow peak at around 378 1C is highly increased with time. As a result of the experimental studies, it was concluded that the reason behind anomalous fading can be explained by means of tunneling (quantum tunneling) mechanism.
Thermoluminescence properties of Mn4+‐doped and La3+, Gd3+, Dy3+ and Ho3+ co‐doped MgAl2Si2O8 host phosphors were investigated in detailed and reported for the first time. The phosphors were exposed to β‐ and α‐irradiation and the glow curves appeared at 260–262 ± 2°C and 245–252 ± 2°C, respectively. Thermoluminescence analysis show that the main glow peaks actually consisted of three distinct peaks (P1, P2 and P3). In addition, all the phosphors had a main peak, and many satellite peaks also appeared up to 200°C. Moreover, it was observed that La3+, Gd3+, Dy3+ and Ho3+ dopants in MgAl2Si2O8Mn4+ phosphor can change the thermoluminescence peak intensities, but they did not cause any new glow peak. In addition, when α‐irradiation was used, the glow peaks were shift to a lower temperature region. Kinetic parameters of P1, P2 and P3 were calculated, and it was found that P1 and P3 had first‐order kinetics and P2 had general‐order kinetic parameters. In addition, it was found that when the easy and convenient annealing procedure was applied to the phosphorus, the thermoluminescence signal was measured as stable over many repetitions. The dose sensitivity, reproducibility and fading features of the powdered phosphors were investigated and computerized glow curve deconvolution analysis was also performed. Results showed that thermoluminescence properties of these materials were good but the fading reliabilities were poor and therefore the sintered or single crystal forms should be preferred for their better fading properties.
The Tm–TSTOP and the variable dose methods were applied to alumina experimentally, and then all the steps of the methods were simulated numerically. The Tm–TSTOP experiments were performed between 70 and 300°C, and results showed that the glow curve of the used alumina had six distinct peaks between 40 and 400°C. The glow curves were analyzed using computerized glow curve fitting programs, the analytical equations were also fitted to the experimental data, and the trapping parameters of the peaks were measured. The samples were irradiated above the saturation level to ensure the complete filling of the electron traps and, therefore, the concentrations of traps were measured experimentally. Short‐term anomalous fading behaviours of the peaks were investigated, and a new equation was proposed to compute the anomalous fading rate. In addition, the variable dose and Tm–TSTOP methods were simulated using the six trap‐one recombination centre (6T1C) model and the experimental trapping parameters. Results showed that there was good harmony between numerical and experimental glow curves. After all the simulations were performed with acceptable accuracy, an estimate was made for the trapping coefficients (Ai = 1–6) that could not be measured directly from thermoluminescence experiments. Results showed that the trapping coefficients were affected by the applied dose.
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