1999 年 48 巻 2 号 p. 107-112
Radiation exposure from a pillow was analyzed. According to an advertisement of the pillow, this radioactive consumer product contains enough amounts of radioactive materials to induce radiation hormesis effects. The pillow consists of the filling chips made from kneading mineral ores and the polynosic lining contains natural radioactive ores.
Aγ-ray analysis of the pillow using pureGe-MCA reveals that there exist radioactivities of thorium and uranium series mixtures in it at concentration of 0.58% by the weight.
The observations of a chip surface by a scanning electron microscope show that the shapes of two sides are different each other. There are lots of sharp protuberances on the outside of the chip.
To determine the direct external exposures from the pillow, film badges were placed on the pillow for 210hand2555h.The dose equivalents of 210hexposure was under 0.1mSvwhich is a detection limit ofa γ-ray by the film badges. However, that of 2555hexposure was over 0.1mSvless than 0.15mSv.
Quantities of internal exposures from inhalation of the vaporizedRnwere measured by a Lucas Cell. It was 79Bq/m3.There is no necessity for anxious about being broken in health inhaling theRn-gass.