Morphological change with soybean root development was investigated non-destructively by neutron radiography. Not only the main root but also the side roots were shown as an clear image on both X-ray and dry films. In the case of dry film, the resolution of the image obtained was about the same as that by X-ray film and the thermal neutron flux was reduced to be about one fifteenth. The image of the root was much clearly obtained in the sand than in the soil where the soil aggregates were randomly shown. In order to know to which degree the root can be shown in the image, the aluminum containers with various thickness were tested. Even when the thickness of the container was increased up to 1.7cm, the image of the main root was clearly observed through the soil. It was shown that by neutron radiography the morphology of the plant root could be traced non-destructively during the development of the plant.
Experiments were made to determine the exposure rate dependence of CO33-signal intensity in ESR dosimetry of tooth enamel. Packages containing 100 mg of mixed tooth enamel of particle size of 500- 850μm were irradiated by 60Co gamma-rays with various exposure rates ranging from 5.17×10-3 to 3.48 C kg-1 h-1 up to a total exposure of about 1290×10-4 C kg-1 (500 R) . The irradiated tooth enamel samples were then subject to ESR measurements and the relative response was determined as a function of exposure rate. The response was found to be almost independent of exposure rate. No significant difference of response is observed between dry-irradiated and wet-irradiated samples.