Basic study on gamma- and X-ray imaging technology using miniature radiation source

In order to visualize a concealed unlawful matter, visualization using X-ray perspective image is effective, which is actualized. However, it is insufficient by conventional X-ray perspective image to visualize matters and substances of light elements such as narcotics, plastic bombs, and so forth, especially those in a metal container. Then, this study aims at basic research on visualization of perspective image on a weapon such as pistol and so on or a light element substance in a metal container such as car by using gamma-ray with various wave-lengths from a small radiation source. In 1998 fiscal year, a photographing system consisting of an X-ray 2 and a cooled CCD camera was constructed to carry out some simple photographing experiments. By judging through this experimental results only, 57Co can be said to be more suitable to gamma-ray source for the perspective image photographing than 137Cs is, which will be a future subject because of supposed dependence of specimen amount, shielding panel thickness or detector. (G.K.)