2017 年 6 巻 1 号 p. 1-5
Electron spin resonance (ESR) spectroscopy in combination with irradiated solid granulated sugars was first examined for use as a radiation dosimeter. The first derivative ESR spectrum obtained from X-irradiated sugars was doubly integrated to derive the actual signal intensity. The amount of free radicals produced in X-irradiated sugars was estimated by comparing with the intensities of the 1.1-diphenyl-2-picrylhydrazyl (DPPH) standard having one spin (radical) in its molecular structure. The linear relationship obtained between the amount of free radicals and the irradiation dose in the range of 33 - 2000 mGy confirmed the applicability of ESR spectroscopy as a dosimeter. Therefore, this method was further applied to measure radiation doses accumulated in the teeth of field mice living around the Fukushima Nuclear Power Plant to assess the impact of the Fukushima nuclear accident that occurred on March 11, 2011. Nineteen field mice were collected between November 15 and 17, 2013. ESR signals of the teeth (40 mg for each) of these mice were compared with those in Hokkaido (non-irradiated controls). However, because of large background ESR signals in both samples, no statistically significant difference was observed between the radiation levels in the teeth of mice collected from Fukushima and those from Hokkaido.
