1. Consiglio Nazionale delle Ricerche & Istituto Officina dei Materiali c/o Institut Laue Langevin, 38042 Grenoble, France
2. Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234, Australia
3. Dipartimento di Fisica e Geologia, Università degli Studi di Perugia and CNISM, Via Pascoli, 06123 Perugia, Italy
4. Institut Laue-Langevin, 38042 Grenoble, France
5. Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany
6. Laboratoire Léon Brillouin (CEA/CNRS), CEA Saclay, 91191 Gif-sur-Yvette Cedex, France