1. JX Nippon Exploration and Development Co., Ltd.
2. Tono Geoscience Center, Japan Atomic Energy Agency
3. Kyoto Fission-Track Co.,Ltd.
4. Center for Regional Development, Akita University
5. Graduate School of Science and Engineering (Science Course), Kagoshima University
6. Oyo Corporation
7. Present address: Geochemical Research Center, Graduate School of Science, The University of Tokyo