Experimental study on source efficiencies of various materials contaminated with radioactivity

A source efficiency was measured experimentally for various materials, such as metals, nonmetals, flooring materials, sheets and other materials, contaminated by alpha- and beta-emitter radioactive nuclides. Five nuclides, 147Pm, 60Co, 137Cs, 204Tl and 90Sr-90Y, were used as the beta emitters, and 241Am was used as the alpha emitter. The source efficiencies of nonpermeable materials were higher than those given by the Japanese Industrial Standards (JIS). In contrast, the source efficiencies of some permeable materials were lower than those given by the JIS because the source efficiency varies depending on whether the materials or radioactive sources are wet or dry. This study provides basic data on the source efficiency for estimating the surface contamination level of materials. (author)