1. Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan, Laboratory for Multiple Isotope Research for Astro- and Geochemical Evolution (MIRAGE), Hiroshima University, Hiroshima 739-8526, Japan, and Institute of Materials Structure Science, Photon Factory, KEK, Tsukuba 305-0801, Japan