Author affiliations
1 Department of Physics, Hirosaki University, Hirosaki 036-8561, Japan
2 Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
3 Faculty of Engineering, Yokohama National University, Yokohama 240-8501, Japan
4 Department of Physics, Hebei Normal University, Shijiazhuang 050016, China
5 Department of Mathematics and Physics, Tibet University, Lhasa 850000, China
6 Department of Physics, Shandong University, Jinan 250100, China
7 Institute of Modern Physics, SouthWest Jiaotong University, Chengdu 610031, China
8 Department of Physics, Yunnan University, Kunming 650091, China
9 Faculty of Engineering, Kanagawa University, Yokohama 221-8686, Japan
10 Faculty of Education, Utsunomiya University, Utsunomiya 321-8505, Japan
11 Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582, Japan
12 Department of Physics, Konan University, Kobe 658-8501, Japan
13 Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555, Japan
14 Department of Physics, Shinshu University, Matsumoto 390-8621, Japan
15 Center of Space Science and Application Research, Chinese Academy of Sciences, Beijing 100080, China
16 Physics Department and Tsinghua Center for Astrophysics, Tsinghua University, Beijing 100084, China
17 Department of Physics, Saitama University, Saitama 338-8570, Japan
18 Advanced Media Network Center, Utsunomiya University, Utsunomiya 321-8585, Japan
19 National Institute of Informatics, Tokyo 101-8430, Japan
20 Tochigi Study Center, University of the Air, Utsunomiya 321-0943, Japan
21 Tokyo Metropolitan College of Industrial Technology, Tokyo 116-8523, Japan
22 Max-Planck-Institut für Physik, München D-80805, Deutschland
23 Shonan Institute of Technology, Fujisawa 251-8511, Japan
24 RIKEN, Wako 351-0198, Japan
25 School of General Education, Shinshu University, Matsumoto 390-8621, Japan
26 Paper presented at the conference by K. Kawata