1. Department of Engineering Physics and Key Laboratory of Particle and Radiation Imaging (Tsinghua University) of Ministry of Education, Tsinghua University, Beijing 100084, China
2. China Spallation Neutron Source, Institute of High Energy Physics, Chinese Academy of Sciences, Dongguan 523000, China
3. Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
4. School of Polymer Science and Engineering, University of Southern Mississippi, Hattiesburg, Mississippi 39406, United States