1. Kyoto University, Research Reactor Institute, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan
2. Kyungpook National University, Institute of High Energy Physics 1370 Sankyuck-dong, Puk-gu, Daegu 702-701, Korea
3. Korea Atomic Energy Research Institute, P.O. Box 105, Taejeon 305-600, Korea