1. European Synchrotron Radiation Facility (ESRF), BP 220, 38043 Grenoble Cedex 9, France
2. Dipartamento di Scienze della Terra, Universitá di Camerino, I-62032 Camerino, Italy
3. J. Stefan Institute, P.O. Box 3000, SI-1001, Ljubljana, Slovenia
4. FYSIKUM, AlbaNova University Center, Stockholm University, S-10691 Stockholm, Sweden