1. Key Laboratory of Particle and Radiation Imaging (Ministry of Education) and Department of Engineering Physics, Tsinghua University, Beijing 100084;,
2. Yalong River Hydropower Development Company, Chengdu 610051
3. INPAC and Department of Physics and Astronomy, Shanghai Laboratory for Particle Physics and Cosmology and Shanghai Jiao Tong University, Shanghai 200240
4. Institute of Physics, Academia Sinica, Taipei 11529;