2015 Volume 64 Issue 2 Pages 123-131
Kelps are very comprehensible educational tools for illustrating naturally existing radiation and radioisotopes due to natural potassium-40 that emits radiations. In the present study, a compression and formation method was applied to 18 varieties of commercially available dried kelps and 18 disk-shaped radiation sources were fabricated. Thus fabricated radiation sources were examined by comparing their dimensions(diameter and thickness), weights and radiation intensities(cpm) from the view point of raw materials of natural radiation sources. It was found that the dimensions of the fabricated radiation sources did not significantly vary by difference of kelp, but radiation intensity changed. The most intensive sources were three times larger than the weakest sources. To estimate the radiation intensity of natural radiation sources before fabricating them, a direct measurement of kelps in a bag was examined.
