1. Nuclear Science and Engineering Center, Japan Atomic Energy Agency, 2-4 Shirane Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
2. Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo 184-8588, Japan
3. Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, 2-4 Shirane Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan