Applied Sciences (Nov 2021)
Investigation of X-ray Radiation Detectability Using Fabricated ZnO-PB Based Extended Gate Field-Effect Transistor as X-ray Dosimeters
Abstract
A new design of the MOSFET dosimeter is being developed in a different study to measure the dose delivered to the tissue layers. Development of zinc oxide-Lead (ZnO-Pb) of different thicknesses fabricated by chemical bath deposition were investigated to study their sensitivity following irradiation using a low absorbed dose that can be used in diagnostic and interventional radiology (9, 36.5, and 70 mGy) and high absorbed dose (1, 5, and 10 Gy) of X-ray. The morphology and structure of the as-prepared films were analysed using FESEM and XRD measurements. The device relies on sensing the changes in the local electric field arising from radiation interactions in the absorber, coupled with the semiconductor materials used in this work—ZnO-Pb as the EGFET. Then the sensitivity of all devices was examined. Generally, thin-film devices showed less sensitivity to X-ray than the disk type. The sensitivity of the thin film dropped from 6.66 mV/to 1.42 mV/Gy, while the sensitivity of the ZnO-Pb disk type was 23.3 mV/Gy, which then dropped to 6.30 6.42 mV/Gy. Furthermore, the disk type ZnO-Pb was exposed to a high absorbed dose and obtained a sensitivity value of 0.08 mV/Gy, while the ZnO-Pb thin film obtained 0.01 mV/Gy. This can be related to the influence of thickness on the sensitivity of the dosimeter. However, the device’s performance characteristics, like sensitivity to radiation exposure and operating dose area, were discovered to be strongly dependent on the materials employed, effective atomic number, and thickness of the materials. Based on the results shown above, these devices might be considered a low-cost candidate for real-time -radiation dosimetry at room temperature. Furthermore, the thickest sample of 1 mm showed better sensitivity to radiation, compared to the thinner samples.
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