Information about radioactive cesium (¹³⁷Cs) distribution on lands with different uses is necessary for future decontamination works. This study investigated the degree of contamination and factors affecting ¹³⁷Cs accumulation in soils and wild plants in areas of different land use after the Fukushima Nuclear Power accident. We measured the level of ¹³⁷Cs in soils and wild plants in Iitate village and neighboring areas in 2014. Results indicated that ¹³⁷Cs in the agricultural soils was 11-14 kBq kg^－1, while the roadside soil with a high clay content showed the highest concentration (261 kBq kg^－1) and the mountain soil with high soil organic matter showed the lowest concentration (6 kBq kg^－1). The ¹³⁷Cs concentrations in wild plants directly reflected those in their respective soils. The ¹³⁷Cs uptake in wild plants did not differ among plant species grown in the same soil but differed within the same plant species grown in different soils.

 Crookes tubes have been used as fundamental equipment for science education in junior-high schools in Japan. However, radiation protection and safety guidelines have not been evaluated sufficiently to date. Estimations of the X-rays radiated from the Crookes tubes under various systematic conditions are required to establish these guidelines. Energy spectrum of the X-rays was obtained by CZT detector with very fine collimator to avoid pile-up effect. The peak energy of the X-rays was about 20 keV, and the most frequent voltage of pulses applied from an induction coil was matched with this peak energy. The correlation between the distribution of the applied voltage and X-ray spectra was obtained in this study. The energy of the X-rays was also estimated by a linear attenuation coefficient of Al plates. The effective X-ray energy estimated by this conventional method showed good agreement with the result obtained by CZT detector.

 The dispersal rates of ²¹¹At, which is a promising nuclide for targeted alpha therapy, from aqueous solutions and chloroform were studied to provide experimental evidence for the reasonable evaluation of its airborne concentration in a radiation-controlled area. Using a collection unit for dispersed ²¹¹At during ventilation, radioactivity of the trapped ²¹¹At was quantified. The dispersal rates of ²¹¹At in chloroform as well as acidic, neutral, and alkaline solutions, in addition to a neutral solution containing ascorbic acid, were determined. Thin-layer chromatography was also performed to identify the formed chemical species of ²¹¹At. The dispersal rate of ²¹¹At was very low in the neutral solution containing ascorbic acid and in chloroform. The chemical forms of ²¹¹At in aqueous solutions are also briefly discussed.