## 3 Results and Discussion
From the above curves, the slopes of the (I\({}_{\text{ds}}\)-Dose value) and (V\({}_{\text{gs}}\)-Dose value) were used to calculate the present sensitivity and linearity of the detector to radiation (Figure 8): \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & **Absorbed Dose** & **Linearity \%** & **Threshold Voltage** & \multicolumn{2}{c}{**Sensitivity**} \\ \cline{3-6}  & **(mGy)** & **(mV)** & **(mV/mGy)** & **(\(\mu\)A/mGy)** \\ \hline \multirow{3}{*}{TF ZnO-Pb} & 9 & & 60 & 6.66 & \\ \cline{2-6}  & 36.5 & 94.5 & 80 & 2.19 & 1.05 \\ \cline{2-6}  & 70 & & 100 & 1.42 & \\ \hline \multirow{3}{*}{1 mm disk ZnO-Pb} & 9 & & 210 & 23.3 & \\ \cline{2-6}  & 36.5 & 96.5 & 230 & 6.30 & 2.28 \\ \cline{1-1} \cline{2-6}  & 70 & & 540 & 7.71 & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Radiation sensing characteristics of ZnO-Pb under low radiation doses and various thicknesses. Figure 7: (**A**) Linear and saturation regime for the thin film and (**B**) linear and saturation regime for the 1 mm disk ZnO-Pb, under high absorbed dose. 5.80 \(\mu\)A/Gy \(\pm\) 0.545 \(\mu\)A, 90.4% for the thin film and 21.5 \(\mu\)A/Gy \(\pm\) 0.14 \(\mu\)A, 96.8% for 1 mm ZnO-Pb, for saturation and linear regimes, respectively. Also, the current rose on increasing the dose in the saturation regime, while the voltage decreases with a rise in the dose in the linear regime from 3.22 V to 2.94 V \(\pm\) 0.028 V for the thin film and from 3.28 V to 3.04 V \(\pm\) 0.02 V for the 1 mm thickness one. The threshold voltage of the samples shows that for all samples, the threshold voltage increased on increasing the absorbed dose value and increasing the thickness of the samples. Because the possibility of particle ionization by photoelectric effect is considerably greater than that by Compton's effect, a greater number of positive trap charge is created during low dose X-ray irradiation than during high dose X-ray irradiation, which obviously impacts the variety of values in the predominance of Compton interaction, as in this case [26]. The sensitivity of the samples decreased on increasing the absorbed dose and increases on increasing the thickness of the samples. Figure 9 shows the threshold voltage and sensitivity plotting for all samples with absorbed dose value. We can notice that 1 mm ZnO-Pb has higher \(\Delta\)V\({}_{\text{TH}}\) value and sensitivity than the other sample with lower thicknesses. The sensitivity of an MOS sensor is greatly dependent on the thickness of gate oxide (T\({}_{\text{OX}}\)). The oxide functions as an ionization chamber, where T\({}_{\text{OX}}\) defines the ionization volume. In addition, as the thickness increases, the capacity of the oxide (C\({}_{\text{OX}}\)) decreases, so that at the same trapped load, the variation in the gate voltage is higher. The sensitivity of MOS dosimeters increases on the one hand with increasing ionization volume, and on the other with decreasing oxide capacity, then increases in T\({}_{\text{OX}}\), twice leading to increases in sensitivity. Therefore, the sensitivity has a dependence approximately proportional to T\({}_{\text{OX}}\)[33]. On the other hand, increasing the absorbed dose up to 10 Gy led to a drop in the sensitivity value for all the samples. This reduction in sensitivity with the applied dose is generated by changes in the functional electric field delivered to the EGFET throughout irradiations, which produces an accumulation of holes just at the oxide gate interface [34]. Table 3 summarizes the results of irradiation to a high X-ray dose. Figure 8: (**A**) Voltage vs. dose and (**B**) current vs. dose for the thin film and disk ZnO-Pb.