Analyzing Tritium Radioactivity in Nihon-shu Specialized by Fukushima Using MAgnetically Levitated Electrode Ionization Chamber

We have conducted a radioactive survey of sake for tritium, which is the isotope of hydrogen with low β-ray energy and is considered difficult to detect and remove. Using a differential-type magnetically levitated electrode ionization chamber (MALIC) developed by Kyushu Sangyo University, we had previously measured gaseous radiation dose (ionization current) for tritium vapor. Based on the result, we analyzed Fukushima specialty sake to determine the radioactive materials and estimated the radioactivity concentration of tritium in sake. As a consequence, our device enabled direct detection at the Japanese drinking water standards level. Besides, we confirmed that the radioactivity concentration of this sake was quite far below the lower limit of the Japan and WHO drinking water standards.