While the period of high growth of Japanese economy, infrastructures were actively constructed. Now the structures are aged and its evaluation of integrity is one of significant topics to keep its serviceability and safety in Japan. Although the authors have been studied on tomographic techniques that are on the basis of elastic wave propagation for the evaluation, elastic wave difficultly propagate inside of structures if the structures are covered by stiff materials, e.g. steel reinforcement, and evaluation of integrity of the structures is difficult as consequence. Further, electromagnetic waves have been widely used for the inspection of concrete structures as well. However, dissipation rate of the electromagnetic waves is generally high in metals, and it is also difficult to penetrate inside of the structures. On the other hand, neutron beam is known as a radioactive ray which permeability is high and it would be applicable for the inspection of inside of the concrete structures. Thus, in this study, permeability of neutron beams to concrete specimens is discussed as preliminary study for establishing the inspection technique of concrete structures with neutron beam.

재배종담배(Nicotiana tabacum L. cv.), 야생종담배 (N. plumbaginifolia)와 벼종자(Orya sativa L, cv.)에 neutron빔을 각각 조사(irradiation)하여 발아, 식물체의 생장과 DNA의 변이에 미치는 영향을 검토하였다. 담배종자와 벼종자에 90, 180, 270, 360, 450, 540 Gy까지 조사로 발아율은 크게 감소하지 않았고, 생장에 있어 유의적인 차이는 없었다. 그러나 담배식물체에서 총 200개체 중 71개체(약 36%)가 잎에서 형태 이상을 나타내었다. 또한 줄기색 변이체, 엽색변이체, 화형변이체를 유도하였다. 이 결과는 neutron빔이 유용한 돌연변이원으로서 가능성이 있음을 시사해 준다. Neutron빔을 조사한 후 생장한 담배식물체의 잎에 대하여 총 34개의 primer를 이용하여 RAPD 분석한 결과 20개의 primer에서 총 104개의 DNA 단편이 증폭되었고, 중성자 빔조사처리구에서만 출현하는 DNA 단편은 나타나지 않았다.