METHOD AND APPARATUS FOR MEASURING RADIOACTIVITY

摘要

PURPOSE:To measure radioactivity of each radioactive nuclide separately at the time of measuring radioactivity of waste contaminated with a plurality of radioactive nuclides. CONSTITUTION:An object 100 to be measured is coated with a phosphor by means of a coater 10 thus forming a phosphor layer on the surface of the object. Fluorescence emitted from the phosphor layer is detected, in the form of fluorescence distribution, by a detecting section 20 and stored in an image memory 34 in the form of digital image. The thickness of phosphor layer is altered stepwise and the fluorescence distribution is detected at each step and stored in the image memory 34. A computor 36 has a characteristic table representative of the relationship between the thickness of phosphor layer and the detection efficiency and the detection efficiency of each radioactive nuclide at each step of thickness is determined with reference to the table. The computor 36 then determines the radioactive distribution for each nuclide using the fluorescence distribution at each step of thickness and the detection efficiency of each nuclide. The radioactive distribution thus determined is presented on a display 38.