Studies on the video imaging of radioactivity distribution

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Until now, the subject of measurement for radioactivity and radiation was mainly the intensity and the energy. It is desirable hereafter that the distribution is rapidly imaged on video monitor in the detection of plutonium contamination, beta-emitter autoradiography and neutron radiography. The purpose of this study is to image the distributions of radioactivity and radiation, to process the image, and to evaluate quantitatively the distributions.A imaging video monitor system for alpha-activity distribution consists of a detection unit, a video imaging unit, a image integration unit, and a image process unit. The video imaging unit was newly constructed on present study. The monitor of the image integration unit displays the image of the distribution becoming gradually clear.The integrated image is transferred to the image process unit to process the image. The integrated image is low noise. The distortion of the image is less than 2.5 %, and the spatial resolution is 1.4 lp/mm. Although the system was improved to place the video imaging unit in contact with the detection unit, the nonuniformity in integrated image was left. In order to evaluated quantitatively the integrated alpha-image, the uniform process and spot process was newly programmed.The imaging video monitor system was applied to the detection of plutonium contamination. The spot image obtained with the image integration unit was processed to uniform image. The processes of the uniformity and ROI gave the alpha-activity on the whole sample. Moreover, the alpha-activity and size distributions of plutonium particles could be obtained by the spot process. These results indicate that the imaging video monitor is a useful means for detecting plutonium contamination and evaluating plutonium exposure. The application to neutron radiography is the subject for a future study.