1. Forschungszentrum Karlsruhe, Institut für Neutronenphysik und Reaktortechnik P.O. Box 3640, D-76021 Karlsruhe, Germany
2. Commission of the European Union, Joint Research Centre Karlsruhe Establishment, European Institute for Transuranium Elements P.O. Box 2340, D-76125 Karlsruhe, Germany
3. European Synchroton Radiation Facility B.P. 220, F-38043 Grenoble Cedex, France