## 3 Results
### Analysis and Structure of TL Emission from Phosphate Glasses
For terbium-doped glass (0.5% Tb\({}_{2}\)O\({}_{3}\), PPG\({}_{7}\)Tb05, cf. Figure 9b) and the lowest heating rate of 0.5 \({}^{\circ}\)C/s, one can easily determine the low temperature peak position at 101 \({}^{\circ}\)C/s and roughly the position of the other, higher temperature peak at ca. 175 \({}^{\circ}\)C. Moreover, for terbium-doped glass the much stronger dependence of the overall TL emission curves vs. heating rate can be easily found. Increasing the heating rate, the intensity of the first peak decreases progressively; however, it can be still easily found even in case of the highest heating rate of 10 \({}^{\circ}\)C/s on the lower temperature shoulder of the most prominent TL emission peak, whose maximum is located at ca. 200 \({}^{\circ}\)C/s. Very similar results based on the VHR method were observed also for the 0.1 and 3.0% Tb\({}_{2}\)O\({}_{3}\)-doped phosphate glasses (PPG_Tb01 and PPG_Tb30). Due to the significant complexity of the presented TL emissions, it is very difficult to completely analyze the structure of the glow curves and contribution of the particular TL peaks taking into account only results obtained from Tmax-Tstop and VHR measurements. Nevertheless, they can be a starting point for the deconvolution analysis using specialized software with implemented appropriate TL models. Based on the data presented above, one can propose models suitable for resolving observed TL glow curves. For the PPG glass, the model involves mixed contribution of FOK peak, three continuous energy distribution peaks, and GOK signal, according to Equation (4):  
\[\text{I}_{\text{TL}}(\text{T})=\text{I}_{\text{Peak1}}^{\text{FOK}}(\text{T})+ \text{I}_{\text{Peak2}}^{\text{Cont}}(\text{T})+\text{I}_{\text{Peak3}}^{ \text{Cont}}(\text{T})+\text{I}_{\text{Peak45}}^{\text{Cont}}(\text{T}) \tag{4}\]  
where ITL and Ipeak (1-5) are total and fractional TL intensities due to the particular peaks contributions. Such a combined approach to TL glow curve analysis has already been  
Figure 9: TL glow curves of PPG (**a**) and terbium-doped phosphate glass (**b**), PPG_Tb05) measured at various heating rates (irradiation dose ca. 10 kGy, terbium-doped glass measured using shutter reducing light intensity ca. 100\(\times\)). applied and reported in literature [49]. The glow peaks following first (FOK) and general order kinetics (GOK) were fitted using Equations (5) and (6) [48; 50]:  
\[\mathrm{I^{FOK}(T)=I_{m}\exp\left(\frac{E}{kT_{m}}-\frac{E}{kT}\right)\exp\left[ -\frac{E}{kT_{m}^{2}}\int_{T_{m}}^{T}\exp\left(\frac{E}{kT_{m}}-\frac{E}{kT^{ \prime}}\right)dT^{\prime}\right] \tag{5}\]  
\[\mathrm{I^{GOK}(T)=I_{m}\exp\left(\frac{E}{kT_{m}}-\frac{E}{kT}\right)\left[1 +\left(\frac{b-1}{b}\right)\frac{E}{kT_{m}}\int_{T_{m}}^{T}\exp\left(\frac{E}{ kT_{m}}-\frac{E}{kT^{\prime}}\right)dT^{\prime}\right]^{-\frac{b}{b-1}} \tag{6}\]  
where I and \(I_{m}\) are TL intensities for a given temperature (T, in K) or at peak maximum (Tm) and temperature linearly increases with time (t) from \(T_{0}\) to T, T(t) = \(T_{0}\) + Pt, \(\beta\) (\({}^{\circ}\)C/s) is the linear heating rate; E (eV) is the trap activation energy; k (eV\(\cdot\)K\({}^{-1}\)) is the Boltzmann constant; and b is the kinetic order parameter. In case of continuous energy distribution of traps present in material, usually exponential or gaussian functions are used, which can be described by Equations (7) and (8) [49; 50; 51]:  
\[\mathrm{n^{Exp}(E)=\frac{n_{0}}{\sigma}\exp\left(-\frac{E-E_{0}}{\sigma}\right)} \tag{7}\]  
\[\mathrm{n^{Gaus}(E)=\frac{n_{0}}{\sqrt{2\pi\sigma^{2}}}\exp\left[-\frac{\left( E-E_{0}\right)^{2}}{2\sigma^{2}}\right]} \tag{8}\]  
where n and no are number of trapping centres of a given energy (E) and total density of trapped charges (cm\({}^{-3}\)), E\({}_{0}\) is either the shallowest energy in the distribution (exponential model) or the most populated trapping level (gaussian distribution), and \(\sigma\) is the parameter related to the width of the distribution.