抄録
Alpha radiations from nuclear waste produced at nuclear power plants is checked and classified according to the radiation level. In the case of conventional detectors that use ZnS (Ag) scintillators, detectors are placed almost in close contact to the nuclear waste because of the short range of alpha particles in the air. Those ZnS detectors have nearly 100-% detection efficiencies to alpha radiation, however, they are only capable of measuring objects with flat surfaces. We have developed alpha-detection systems that detect alpha-induced UV lights from some distance away. To operate the systems in the high-gamma-ray environment, we developed Alpha Camera that improved UV sensitivity while reducing the gamma-ray background drastically. We have carried out demonstrations of Alpha Camera where an Am-241 alpha source of 0.2 kBq/100 cm^2 was imaged from 1-m away. Alpha Camera successfully identified a 0.2-kBq/100 cm^2 alpha emitter with a 60-sec measurement.
