Experimental discussion has been made in this paper about the simulated expriment of the sky shine in water. Measurements of the dose rate of gamma-rays from a point source of 60Co in an infinite water medium have been made. Ionization chambers were used for measurement of the dose rate. A satisfactory agreement was obtained between dose buildup factor given by this experimental results in water and those given by the calculated results in air. It is found that this simulated experiment in water offers the valuable information concerning the sky shine from the results of this study.
A method for simulating the effect of radiation at a certain point inside of vehicle originating the infinite surface contaminated uniformly with the radioactive material, has been studied. On the circumference of radius of about the length of a vehicle, a pole is set on which radioactive sources are distributed depending upon the distribution function calculated in this paper. The dose-rates of radiation at the same point are measured in the both cases: one is inside the vehicle and the other without vehicle and the ratio between both cases was calculated, which indicates the shielding-coefficient. An experimental example has also been made using a special vehicle. The shielding-coefficint of this vehicle was about 6%.
LiF thermoluminescent dos meters were used to measure the dose rates in a high-level gamma irradiation facility which provides a wide range in dose level and various irradiation areas. A comparison of the discrepancies between observed data and calculated data based on a cylindrical source, point source, and line source is included.
Self-luminous compound emits a light by the excitation of the radiation. As a radiation source for self-luminous compound promethium-147 or tritium is used recently. In Nemoto Tokushu Kagaku Takaido Factory the radioactive luminous compound has been produced and applied to dails and hands of watch and clock from 1960 to the present time. In this paper the working methods and the radiation monitoring such as personal control, air dust monitoring, surface contamination and wastes control in this factory are discribed.
The characteristic distribution of radioactive fallout 90Sr and 137Cs absorbed into a Satsuma orange fruit was investigated. After peeling, the so-called edible part of the fruit was divided into two parts by use of an autojuicer. One was juice including interior cells of vesicle and a part of vesicle, the other was residue including the vesicle, vascular bundle and carpet wall. The ratio of 90Sr concentration in juice to that in risidue part was found to be three vs. seven, while this ratio was seven vs. three for 137Cs concentration. When expressed in Sr unit, the values (266-422pCi/g Ca) of the residue part were about six times as much as the juice part and about two to three times as much as the rind part. When expressed in Cs unit, the values (88-133pCi/g K) of the rind part was about five times as much as the residue part or the juice part, and the residue and the juice part had almost the same value. For practical purpose, it is more convenient to express 90Sr or 137Cs concentration in orange fruit by content of the nuclide in juice per unit weight of fresh fruit than by the nuclide content per unit weight of so-called edible part of fresh sample.