1. Institute
for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581, Japan
2. Jülich
Center for Neutron Science at the Spallation Neutron Source, Oak Ridge
National Laboratory, Oak Ridge, Tennessee 37831, United States
3. Department
of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan