A study on internal contaminations of twenty-one cyclotron workers in two establishments is reported. The main objective in this study is to trace the relationships between the occurrence of internal contamination and the environmental conditions of working area. Factors concerned with the occurrence of internal contamination area: 1. environmetnal contamination in working area 2. poor experiences of a worker in operation 3. unreasonable increase in working frequency and intensity 4. indifferent attitude towards radiation safety 5. carelessness about the apportionment of work amountto operators. From a heaith physics standpoint, emphasis is placed upon the importance of planning and training in cyclotron operation.
Application of the lognormal function to the particle size distribution of radioactive aerosol, radiation dose rate in controlled working areas, and radioactive air concentration has been investigated by a few workers. This paper discusses the distribution function on the surface contamination data collected routinely in the controlled working area and shows that the data obey the Rosin-Rammler law rather than the lognormal one.
The possibility to estimate the size distriution of uranium oxide particles by alpha-ray spectrometry was investigated. Alpha-ray spectrometrical measurements were made of several samples of uranium oxide particles of different sizes which were prepared by the sedimentation method. It was found that rough estimation of the size distribution of uranium oxide particles is possible for the particles in a size range of 0.5-10μ in diameter by measuring the shift of the peak position and the broadening of the peak width.