Application of tracers, shielded small-size radiation sources, and non-destructive inspections in industry

In order to measure flow speed and amounts of raw materials for process control at production process, tracer application measuring radioactivity from outer side by mixing radioisotope into the raw materials was often carried out, and then proposed required data for automation of this process by using a computer. However, this method could be only used for a study in a laboratory because any radioisotope used at production field was legally for bidden to make a product even at any low concentration. And, for non-destructive inspection as one of quality control, gamma-ray radiography using shielded gamma-ray source was added to X-ray inspection carried out for a long time. Some testers using shielded small-size addition sources such as thickness tester, densimeter, moisture tester, sulfur tester, and so forth are also actually used since many years ago, and 13,400 sets of testers containing non-destructive inspection apparatus are now used at private companies in all-over of Japan. (G.K.)