X-ray Radiation Effects on SWCNT/PMMA Thin Film Nanocomposites

This paper studies the response of a radiation sensor that was developed from single-walled carbon nanotube (SWCNT) and poly (methyl methacrylate) (PMMA) nanocomposite thin films placed on an interdigitated electrode (IDE). We studied the effects of X-rays in real-time electrical resistance of the thin film nanocomposites. A 160 kV X-ray source irradiated the nanocomposite devices with ionizing X-ray radiation at different doses and dose rates, causing the decrease in resistance of thin film through the production of charge carriers. The embedded SWCNT network helped transport radiation-induced electrons to the electrodes. Pre-irradiation resistance can be obtained rapidly from heat treatment of irradiated nanocomposite devices. It is observed that the required heat treatment time for thin film device recovery increased almost linearly with applied radiation dose. The thin film devices were operated at dc voltage as low as 0.05 V for reliable measurement of the radiation-induced change in electrical resistance. The results of this study suggest that SWCNT/PMMA thin film devices could be used for sensing X-ray radiation, with significantly higher sensitivity than comparable devices made with multi-walled CNT (MWCNT) based nanocomposites in a previous study.