1. RIKEN Nishina Center for Accelerator-Based Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
2. Atomic Physics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
3. Electron Tube Division, Hamamatsu Photonics KK, 314-5, Shimokanzo, Iwata-City, Shizuoka 438-0193, Japan
4. Tokyo Branch Office, Hamamatsu Photonics KK, 3-8-21, Toranomon, Minato-ku, Tokyo 105-0001, Japan