1. SPring-8/RIKEN, Mikazuki, Sayo, Hyogo 679-5148
2. Department of Physics, Faculty of Science and Technology, Keio University, Hiyoshi, Yokohama 223-8522
3. Department of Materials Science and Engineering, Muroran Institute of Technology, 27-1 Mizumoto-cho, Muroran, Hokkaido 050-8585