1. Japan Atomic Energy Research Institute, Synchrotron Radiation Research Center, SPring-8, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo, 679-5148
2. Department of Physics, Uppsala University, Box 530, SE-751 21, Uppsala, Sweden
3. Institute of Physics, Tartu University, Riia 142, EE-510 14 Tartu, Estonia
4. Department of Applied Physics, Tokyo University of Science, Shinjuku-ku, Tokyo 162-8601
5. Department of Applied Physics, Nagoya University, Nagoya 464-8603