1. Osaka Laboratory for Radiation Chemistry, Japan Atomic Energy Research Institute, Mii-Minami 25-1, Neyagawa, Osaka 572, Japan
2. Kansai Research Establishment, Japan Atomic Energy Research Institute, Mii-Minami 25-1, Neyagawa, Osaka 572, Japan
3. Radiation Application Development Association, Osaka Laboratory for Radiation Chemistry, Mii-Minami 25-1, Neyagawa, Osaka 572, Japan
4. Japan Synchrotron Radiation Research Institute, Kanaji 1503-1, Hyogo, Kamigori 678-12, Japan