1. Joint Research Center for Atom Technology (JRCAT)Angstrom Technology Partnership (ATP) and JRCATNational Institute for Advanced Interdisciplinary Research (NAIR), 1-1-4 Higashi, Tsukuba, Ibaraki 305-0046, Japan
2. Tsukuba Research Laboratory, Hamamatsu Photonics K. K., 5-9-2 Tokodai, Tsukuba, Ibaraki 300-2635, Japan