1. Dipartimento di Fisica “E. Fermi”, Università di Pisa and Istituto per Processi Chimico-Fisici—Consiglio Nazionale delle Ricerche, Largo Pontecorvo 3, Pisa 56127, Italy
2. ISIS Neutron and Muon Facility, Rutherford Appleton Laboratory, Science & Technology Facilities Council, Didcot OX11 0QX, United Kingdom
3. National Institute of Standards and Technology (NIST), NIST Center for Neutron Research, Gaithersburg, Maryland 20899, United States
4. Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, United States
5. Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37931, United States