1. Laboratory for Neutron Scattering, ETH Zurich & Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
2. Laboratoire de Cristallographie, Le Cubotron, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
3. Institute for Energy Technology, P.O. Box 40, NO-2027 Kjeller, Norway