Dose responses of scattered- and direct-X-ray-irradiated CR-39 and methylviologen-encapsulated silica nanocapsule-doped CR-39 and their mechanisms

•CR-39 and MV2+@SiO2 –CR-39 exhibited some photoemission properties applicable to X-ray detection.•Benzophenone radicals were formed in CR-39 upon X-ray irradiation at 10 to 30 Gy, and the fluorescence intensity increased with the dose.•Methylviologen in SiO2 NCs competitively captured electrons generated by X-ray irradiation, which were reverse transferred to shallow traps with time.•A dose rate of 300 µGy/s was observed for scattered X-rays of 1 and 5 Gy.•Pre–X-ray-irradiated CR-39 rods could be used to detect a dose less than 2 mGy of scattered X-rays using fluorescent images. The photoexcited emissions of direct- and scattered-X-ray-irradiated CR-39 and methylviologen-encapsulated silica nanocapsule (MV2+@SiO2 NC)-doped CR-39 were observed, and they showed a dose response. The benzophenone radical was formed in a shallow trap in CR-39 upon X-ray irradiation from 10 to 30 Gy, and the fluorescence intensity increased with the dose. Methylviologen in SiO2 NCs competitively captured electrons generated by X-ray irradiation, and the captured electrons were reverse transferred to the shallow traps with time. A minimum dose rate of 300 µGy/s was observed between 1 and 5 Gy. Finally, a dose response of less than 2 mGy for scattered X-rays was obtained in this system.