1. Osaka University, Graduate School of Engineering, Division of Electrical, Electronic, and Infocommunications Engineering, Osaka, Japan
2. Service d’Astrophysique, IRFU/DRF, CEA Saclay, Gif-sur-Yvette, France
3. Université de Paris/CNRS, Laboratoire Astroparticule et Cosmologie, Paris, France
4. Institut de Recherche d’Astrophysique et Planétologie, Toulouse, France
5. University of Bergen, Birkeland Centre for Space Science, Bergen, Norway
6. Nagoya University, Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya, Japan