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河地 有木; 尹 永根; 鈴井 伸郎; 石井 里美; 吉原 利一*; 渡部 浩司*; 山本 誠一*; 藤巻 秀
no journal, ,
We newly developed a gamma camera specific for plant nutritional research, and performed quantitative analyses on uptake and partitioning of radiocesium in intact plant bodies. A single-crystal scintillator, Ce-doped GAGG, was employed, which has a relatively high density, a large light output, no natural radioactivity and no hygroscopicity. A 44 44 matrix of the Ce:GAGG pixels, with dimensions of 0.85 mm
0.85 mm
10 mm for each pixel, was coupled to a high-quantum efficiency position sensitive photomultiplier tube. By using this gamma camera, soybean plants, grown in hydroponic solutions and fed with 1-2 MBq of
Cs, were imaged for 6.5 days in maximum to investigate and visualize the uptake dynamics into/within the aerial part. As a result, radiocesium gradually appeared in the shoot several hours after feeding of
Cs, and then accumulated intensively in the maturing pods and seeds in a characteristic pattern. Our results also demonstrated that this gamma-camera method enables quantitative evaluation of plant ability to absorb, transport, and accumulate radiocesium under various experimental conditions.
吉原 利一*; 橋田 慎之介*; 河地 有木; 長尾 悠人; 山口 充孝; 鈴井 伸郎; 尹 永根; 藤巻 秀
no journal, ,
Radiocesium from the severe accident at the Fukushima Dai-ichi Nuclear Power Plant on 11 March 2011 contaminates large areas. After this, a doubt for forest products, especially of mushroom, is indelible at the areas. Pruned woody parts and litters are containing a considerable amount of radiocesium, and generates a problem at incineration and composting. These mean that more attentive survey for each subject is expected; however, the present survey system is highly laborious/expensive and/or non-effective for this purpose. On the other hand, we can see a glass-badge based radiation dose rate detection system. This system always utilized to detect a personal cumulative radiation dose, and thus, it is not suitable to separate a radiation from a specific object. However, if we can separate a radiation from a specific object and relate it with the own radiocesium concentration, it would enable us to presume the specific concentration with just an easy monitoring but without a destruction of the target nature and a complicated process including sampling, pre-treatment, and detection. Here, we present the concept of the measurement and results of the trials.
飯島 和毅; 舟木 泰智; 大山 卓也; 新里 忠史; 佐藤 治夫*; 油井 三和
no journal, ,
F-TRACEプロジェクトの目的は、土壌粒子に強く吸着された放射性核種が森林から海まで河川水系を通しての移動挙動を予測する現象論モデルを開発し、被ばく線量の変化を評価、移動を抑制する方法を提案することである。本研究では、福島沿岸域の一つの河川水系を対象に、放射性セシウムの挙動を概観した。その結果、90%以上のセシウムが森林表土の表面から5cm以内に存在し、湖水中のセシウム濃度が極めて低いことから、河川水系における移動において、放射性セシウムは土壌粒子に強吸着されていると考えられた。また、河川水系中の堆積物の放射性セシウム濃度の違いは、セシウム吸着のサイト密度に及ぼす粒径の影響で説明できる。