1. School of Physics, Sun Yat-sen University, 510275 Guangzhou, China
2. State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, 510275 Guangzhou, China
3. Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing, China
4. Spallation Neutron Source Science Center, 523803 Dongguan, China