1. Ohio University, Department of Physics and Astronomy Clippinger Labs, Athens, Ohio 45701
2. EC-JRC-Institute for Reference Materials and Measurements Retieseweg 111, B-2440 Geel, Belgium
3. Institute of Isotopes of the Hungarian Academy of Sciences Department of Nuclear Research, Budapest, Hungary
4. Forschungszentrum Karlsruhe, Institut für Neutronenphysik und Reaktortechnik D-76344 Eggenstein-Leopoldshafen, Germany